Glossary-Definitions-Clinical Practice, Statistics and Research

By Ted Nissen M.A. M.T.

Copyright © May 2021 Ted Nissen

AbscissaThe horizontal or X axis of a graph.

Absolute ValueThe value of a number without consideration of its algebraic sign.

AdditiveCan legitimately be summed.

Anthropometry refers to the measurement of the human individual. An early tool of physical anthropology, it has been used for identification, for the purposes of understanding human physical variation, in paleoanthropology and in various attempts to correlate physical with racial and psychological traits. Wikipedia

Alpha Level The significance level α is the probability of making the wrong decision when the null hypothesis is true. Alpha levels (sometimes just called “significance levels”) are used in hypothesis tests. Usually, these tests are run with an alpha level of .05 (5%), but other levels commonly used are .01 and .10.

Alternative HypothesisThe hypothesis that the mean of the population treated in a certain way is not equal to the mean of the population not treated in that way; symbolized HI, .

Analysis of Variance (ANOVA)A statistical method for determining the significance of the differences among a set of means.  Analysis of variance (ANOVA) is an analysis tool used in statistics that splits an observed aggregate variability found inside a data set into two parts: systematic factors and random factors. The systematic factors have a statistical influence on the given data set, while the random factors do not. Analysts use the ANOVA test to determine the influence that independent variables have on the dependent variable in a regression study.

Annotated Bibliography- An annotated bibliography or annotated bib is a bibliography (a list of books or other works) that includes descriptive and evaluative comments about the sources cited in your paper. These comments are also known as annotations. A brief summary of the source. 1.) The source's strengths and weaknesses. 2.) Its conclusions. 3.) Why the source is relevant in your field of study. 4.) Its relationships to other studies in the field. 5.) An evaluation of the research methodology (if applicable) 6.) Information about the author's background  Annotated Bibliography    Annotated Bibliography Samples

anterior superior impingement (ASI) Anterosuperior glenoid impingement is a well known and well documented cause of shoulder pain, which occurs after deep surface tears of the subscapularis retract and subsequently become trapped between the anterosuperior glenoid and humeral head. Pain is typically elicited when the shoulder is flexed with internal rotation.

AsymptoticA line that continually approaches but never reaches a specified level.

Bar GraphA frequency graph for nominal or qualitative data. Bars are raised from each designation of a nominal variable on the X axis to the level of its frequency on the axis. Space is left between the bars.

Biased SampleA sample that does not provide all members of the population an equal prob­ability of selection.

Bimodal DistributionA distribution with two modes.

Binomial DistributionA distribution of events that have only two possible outcomes.

Bivariate Distribution. A joint distribution of two variables, the individual scores of which are paired in some logical way.

Cell. The portion of an ANOV A table containing the scores of subjects treated alike.

Central Limit Theorem. The theorem in mathematical statistics that the sampling distribution of the mean approaches a normal curve as gets larger, and that the standard deviation of this sampling distribution is equal to CT/VN.

Central Value. The mean, median, or mode; a statistic that describes the typical score in a dis­tribution.

Chi Square Distribution. A theoretical sampling distribution of chi square values. There is a chi square distribution for each number of degrees of freedom.

Class Interval. A range of scores grouped together in a grouped frequency distribution.

Concentric Exercise Muscle contraction Muscle contraction is the activation of tension-generating sites within skeletal muscle fibers. In physiology, muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in muscle length, such as when holding a heavy book or a dumbbell at the same position. The termination of muscle contraction is followed by muscle relaxation, which is a return of the muscle fibers to their low tension-generating state. concentric exercise - Bing images

Coefficient of Determination. A squared correlation coefficient; an estimate of common variance.

Common Variance. Variance held in common by two variables. It is assumed to be determined or caused by the same factors.

Confidence Interval. An interval of scores within which, with specified confidence, a para­meter is expected to lie. Alpha levels can be controlled by you and are related to confidence levels. To get α subtract your confidence level from 1. For example, if you want to be 95 percent confident that your analysis is correct, the alpha level would be 1 – .95 = 5 percent, assuming you had a one tailed test. For two-tailed tests, divide the alpha level by 2. In this example, the two tailed alpha would be .05/2 = 2.5 percent. See: One-tailed test or two? for the difference between a one-tailed test and a two-tailed test.                       .

Confidence Limits. Two numbers that define the boundaries of a confidence interval.

Constant. A mathematical value that remains the same within a series of operations; for ex­ample, regression coefficients and have the same value for all predictions from the same regression line.

Control Group. A group in an experiment against which other groups are compared.

Correlated-Samples Design. An experimental design in which measures from different groups are not independent of each other. Some writers call this a dependent-samples design.

Correlation. A relationship between variables such that increases or decreases in the value of one variable tend to be accompanied by increases or decreases in the other.

Critical Region. The area of the sampling distribution that covers the values of the test statistic that are not due to chance.

Critical Value. The value from a sampling distribution against which a computed statistic is compared to determine whether the null hypothesis may be rejected.

Degrees of Freedom. The number of observations minus the number of necessary relations obtaining among these observations.

Dependent Variable. The variable that is measured and analyzed in an experiment. Its values are tested to determine whether they are dependent upon values of the independent variable.

Descriptive Statistic. Index number that summarizes or describes a set of data.

Deviation Score. A raw score minus the mean of the distribution from which the raw score was drawn.

Dichotomous Variable. A variable taking two, and only two, values.

Distribution-Free Statistics. Statistical methods that do not assume any particular population distribution.

Empirical Distribution. An arrangement from highest to lowest of actual scores from real observations. .

Endnote-Note citing a particular source or making a brief explanatory comment placed at the end of a research paper and arranged sequentially in relation to where the reference appears in the paper.

Endothelial- the tissue which forms a single layer of cells lining various organs and cavities of the body, especially the blood vessels, heart, and lymphatic vessels. It is formed from the embryonic mesoderm. Compare with epithelium.

Epithelium- is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of cells. Epithelial tissues line the outer surfaces of organs and blood vessels throughout the body, as well as the inner surfaces of cavities in many internal organs. An example is the epidermis, the outermost layer of the skin. There are three principal shapes of epithelial cell: squamous, columnar, and cuboidal. These can be arranged in a single layer of cells as simple epithelium, either squamous, columnar, or cuboidal, or in layers of two or more cells deep as stratified (layered), or compound, either squamous, columnar or cuboidal. In some tissues, a layer of columnar cells may appear to be stratified due to the placement of the nuclei. This sort of tissue is called pseudostratified. All glands are made up of epithelial cells. Functions of epithelial cells include secretion, selective absorption, protection, trans cellular transport, and sensing. Epithelial layers contain no blood vessels, so they must receive nourishment via diffusion of substances from the underlying connective tissue, through the basement membrane. Cell junctions are well employed in epithelial tissues.

Error Variance. Variance due to factors not controlled in the experiment; within-group variance.

Eccentric exercise Eccentric exercise or resistance training is currently being used as a form of rehabilitation for sport injuries, but also as an alternative form of exercise for the elderly, those affected by neurological disorders, COPD, cardiopulmonary disorders, and cancer. Muscle loss is a big problem faced by the people afflicted with the above disorders and many cannot participate in rigorous exercise protocols. Eccentric muscle contractions produce high forces with low-energy cost. According to Hortobágyi due to these properties eccentric exercise has the greatest potential for muscle strengthening. To strengthen muscle the external force must exceed the muscle while it lengthens. The definition of eccentric contraction is almost the exact definition of muscle strengthening. Perceived Muscle Damage: There is a stipulation regarding eccentric contractions in that they actually cause muscle damage and injury. Eccentric contraction may result in delayed onset muscle soreness however; the contraction itself does not cause muscle damage or injury. eccentric exercise - Bing images

Exercise-induced muscle injury (EMI)- in humans frequently occurs after unaccustomed exercise, particularly if the exercise involves a large amount of eccentric (muscle lengthening) contractions. Direct measures of exercise-induced muscle damage include cellular and subcellular disturbances, particularly Z-line streaming.

Expected Value. The mean value of a random variable over an infinite number of samplings. The expected value of a statistic is the mean of the sampling distribution of the statistic.

Experimental Group. A group that receives a treatment in an experiment and whose dependent­ variable scores are compared with those of a control group.

Extraneous Variable. A variable, other than the independent variable, that may affect the dependent variable.

F Distribution. A theoretical sampling distribution of values. There is a different distribu­tion for each combination of degrees of freedom.

flow-mediated dilation (FMD) Flow-mediated dilation (FMD) refers to dilation (widening) of an artery when blood flow increases in that artery. The primary cause of FMD is release of nitric oxide by endothelial cells. To determine FMD, brachial artery dilation following a transient period of forearm ischemia is measured using ultrasound. https://en.wikipedia.org/wiki/Flow-mediated_dilation#:~:text=Flow%2Dmediated%20dilation%20(FMD),ischemia%20is%20measured%20using%20ultrasound

F Test. A method of determining the significance of the difference among two or more means.

Factor. Independent variable.

Factorial Design. An experimental design using two or more levels of two or more factors and permitting an analysis of interaction effects between independent variables.

Footnote-Note citing a particular source or making a brief explanatory comment placed at the bottom of a page corresponding to the item cited in the corresponding text above.

Frequency. The number of times a score occurs in a distribution.

Frequency Polygon. A graph with quantitative scores on the X axis and frequencies on the

functional/microinstability leading to RC tendinosis/tendinopathy- The overhead throwing athlete is an extremely challenging patient in sports medicine. The repetitive microtraumatic stresses and extreme ranges of motion observed within the athlete’s shoulder joint complex during the throwing motion constantly place the athlete at risk for injury. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3811734/

axis. Each point on the graph represents a score and the frequency of occurrence of that score. Points are connected by a line.

Goodness of Fit. Degree to which observed data coincide with theoretical expectations.

Grand Mean. The mean of all the scores in an experiment.

Grouped Frequency Distribution. An arrangement of scores from highest to lowest in which scores are grouped together into equal-sized ranges called class intervals. The number of scores occurring in each class interval is placed in a column beside the appropriate Class interval.

Hawthorne Effect-The Hawthorne Effect refers to the fact that people will modify their behavior simply because they are being observed. The effect gets its name from one of the most famous industrial history experiments that took place at Western Electric's factory in the Hawthorne suburb of Chicago in the late 1920s and early 1930s. The Hawthorne Effect occurs when individuals adjust their behaviour as a result of being watched or observed. For instance, employees may work harder and more diligently knowing their manager is closely watching, or children behave better because they are being watched by their parents.

Hyperemia Active hyperemia happens when there’s an increase in the blood supply to an organ. This is usually in response to a greater demand for blood — for example, if you’re exercising.

Passive hyperemia is when blood can’t properly exit an organ, so it builds up in the blood vessels. This type of hyperemia is also known as congestion.

HHistogram. A graph with quantitative scores on the X axis and frequencies on the

Y axis. A bar covering the range from the lower to upper limit of each score or class interval is raised to the level of that score's frequency. There is no space between the bars.

Hypothesis. A statement about the relationship between two or more phenomena.

Hypothesis Testing. The process of hypothesizing a parameter and comparing (or testing) the parameter with an empirical statistic in order to decide whether the parameter is reasonable. Hypothesis Testing Tutorial

Independent. Events that have nothing to do with each other. Occurrence or variation of one does not affect the occurrence or variation of the other. Two sets of uncorrelated scores are

independent of each other.

Independent-Samples Design. An experimental design using samples whose dependent-variable scores cannot logically be paired.

Independent Variable. The treatment variable; it is selected by the experimenter.

Inferential Statistics. A method of deciding between two or more alternative conclusions.

Interaction. A relationship between two factors such that the effect of one treatment on the dependent variable depends upon the level of the other treatment.

Interpolation. A method for determining a value known to lie between two other values.

interquartile range (IQR)- The IQR describes the middle 50% of values when ordered from lowest to highest. To find the interquartile range (IQR), ​first find the median (middle value) of the lower and upper half of the data. These values are quartile 1 (Q1) and quartile 3 (Q3). Interquartile range

Interval Scale. A measurement scale in which equal differences between numbers stand for equal differences in the thing measured. The zero point is arbitrarily defined.

Least-Squares Solution. Method of fitting a regression line such that the sums of the squared deviations from the straight regression line will be a minimum.

Level. A treatment chosen from an independent variable.

Level of Confidence. The confidence (1 - a) that a parameter lies within a given interval.

Level of Significance. The probability level at which the null hypothesis is rejected.

Line Graph. A graph presenting the relationship between two variables.

Linearity. The condition wherein the "line of best fit" through a scatterplot is a straight line. Lower Limit. The bottom of the range of possible values that a score on a quantitative variable

can take; for example, a score of 5 has 4.5 as its lower limit.

Main Effect. The deviation of one or more treatment means from the grand mean.

Mann-Whitney U Test. A nonparametric method used to determine whether two sets of ranked data based on two independent samples came from the same population.

Matched Pairs. A correlated-samples design in which pairs of scores are matched.

Mean. The arithmetic average; the sum of the scores divided by the number of scores.

Mean Square. An ANOV A term for the variance; a sum of squares divided by its degrees of freedom.

Median. The point that divides a distribution of scores into two equal halves, so that half the scores are above the median and half are below it.

Meta-Analysis -What Is a Meta-Analysis? There are several ways that individual studies can be summarized to help healthcare workers make decisions, including narrative reviews, systematic reviews, and meta-analyses. Both narrative and systematic reviews are both qualitative in nature. Narrative reviews are not very rigorous, but they focus on the very basics of a topic. Systematic reviews are more rigorous than narrative reviews; they focus on a single research question. For example, a systematic review will focus specifically on the relationship between cervical cancer and long-term use of oral contraceptives, while a narrative review may be about cervical cancer. Meta-analyses are quantitative and more rigorous than both types of reviews. In addition to providing an overview, these papers provide a quantitative assessment of how well a treatment works or they may also provide an estimate of how much more likely a person is to develop a disease if they participate in a certain behavior.

Mode. The score that occurs most frequently in a distribution.

Multiple Comparisons. Tests of differences between treatment means or combinations of means following an ANOV A.

Multiple Correlation. A correlation method that combines intercorrelations among more than two variables into a single statistic.

Natural Pairs. A correlated-samples design, in which pairing occurs prior to the experiment.

Nitroglycerin-induced dilation Nitroglycerine- induced vasodilation, an index of endothelium-independent vasodilation, assessed by sublingual administration of nitroglycerine, has been used as a control test for FMD measurement to differentiate endothelium-dependent from endothelium-independent vasodilation because both endog- enous Nitroglycerine-induced vasodilation has been used as a control test for flow-mediated vasodilation (FMD) to differentiate endothelium-dependent from endothelium-independent response when evaluating endothelial function in humans. Recently, nitroglycerine-induced vasodilation has also been reported to be impaired in patients with atherosclerosis.

Nominal Scale. A scale of measurement in which numbers are used simply as names and have no real quantitative value.

Nonparametric Methods. Statistical methods that do not require the estimation of parameters.

Normal Distribution. A theoretical distribution based on frequency of occurrence of chance events.

Normality. The condition of being distributed in the form of the normal curve.

Null Hypothesis. The assumption that the difference between an observed statistic and a pro­posed parameter is the result of chance.

Observed Frequency. Number of observations actually occurring in a category.

One-Tailed Test. A statistical test in which the critical region lies in one tail of the distribution. https://www.statisticshowto.com/probability-and-statistics/hypothesis-testing/one-tailed-test-or-two/

Operational Definition. A definition that specifies a concrete meaning for a variable. The vari­able is defined in terms of the operations of the experiment; for example, hunger may be defined as "24 hours of food deprivation."

Ordinal Scale. A rank-ordered scale of measurement in which equal differences between num­bers do not represent equal differences between the things measured.

Ordinate. The vertical or axis of a graph.

Orthogonal. Independent; uncorrelated.

Parameter. Some numerical characteristic of a population.

Parameter Estimation. Estimating one particular point to be the parameter of a population.

Partial Correlation. Technique that allows the separation or partialing out of the effects of one variable from the correlation of two other variables.

Population. All members of a specified group.

posterior superior impingement(PSI) Posterosuperior impingement, also known as internal impingement, is a relatively uncommon form of shoulder impingement primarily involving the infraspinatus tendon and the posterosuperior glenoid labrum. It occurs when the shoulder is abducted and externally rotated (ABER position). Clinical presentation patients present with posterior shoulder pain and instability. It almost exclusively occurs in athletes who repetitively place their shoulder into extreme abduction and external rotation such as throwers, swimmers, volleyball players and tennis players. Pathology The extreme abduction and external rotation results in repeated impingement of the infraspinatus tendon and the posterior portion of the supraspinatus tendon between the head of the humerus and the posterior superior rim of the glenoid. There is resulting tendon degeneration, reactive humeral head cysts, and glenoid labrum degeneration.  https://radiopaedia.org/articles/posterosuperior-impingement-of-the-shoulder?lang=us

power analysis-The a priori power analysis is what is usually done when designing a study. This tells you what sample size is needed to detect some level of effect with inferential statistics (i.e. with p- values). ... It is important to note that study design impacts power calculations and the interpretation of effect sizes.

Proportion. A part of a whole.

P-Value= probability that the significant differences between groups is due to chance alone. The p value is the evidence against a null hypothesis. The smaller the p-value, the stronger the evidence that you should reject the null hypothesis. P values are expressed as decimals although it may be easier to understand what they are if you convert them to a percentage. For example, a p value of 0.0254 is 2.54%.  https://www.statisticshowto.com/probability-and-statistics/statistics-definitions/p-value/#:~:text=The%20p%20value%20is%20the,value%20of%200.0254%20is%202.54%25

Qualitative Variable. A variable that exists in different kinds; measured on a nominal scale.

Quantitative Variable. A variable that exists in different amounts.                  .

Randomized, blinded trial- Blinded RCTs are commonly used to test the efficacy of medical interventions and may additionally provide information about adverse effects, such as drug reactions. A randomized controlled trial can provide compelling evidence that the study treatment causes an effect on human health.

Randomized controlled trial (or randomized control trial; RCT) is a type of scientific experiment (e.g. a clinical trial) or intervention study (as opposed to observational study) that aims to reduce certain sources of bias when testing the effectiveness of new treatments; this is accomplished by randomly allocating subjects to two or more groups, treating them differently, and then comparing them with respect to a measured response. One group—the experimental group—receives the intervention being assessed, while the other—usually called the control group—receives an alternative treatment, such as a placebo or no intervention. The groups are monitored under conditions of the trial design to determine the effectiveness of the experimental intervention, and efficacy is assessed in comparison to the control.  There may be more than one treatment group or more than one control group.The trial may be blinded, meaning that information which may influence the participants is withheld until after the experiment is complete. A blind can be imposed on any participant of an experiment, including subjects, researchers, technicians, data analysts, and evaluators. Effective blinding may reduce or eliminate some sources of experimental bias.The randomness in the assignment of subjects to groups reduces selection bias and allocation bias, balancing both known and unknown prognostic factors, in the assignment of treatments. Blinding reduces other forms of experimenter and subject biases.A well-blinded RCT is often considered the gold standard for clinical trials. Blinded RCTs are commonly used to test the efficacy of medical interventions and may additionally provide information about adverse effects, such as drug reactions. A randomized controlled trial can provide compelling evidence that the study treatment causes an effect on human health.The terms "RCT" and "randomized trial" are sometimes used synonymously, but the latter term omits mention of controls and can therefore describe studies that compare multiple treatment groups with each other in the absence of a control group. Similarly, the initialism is sometimes expanded as "randomized clinical trial" or "randomized comparative trial", leading to ambiguity in the scientific literature. Not all randomized clinical trials are randomized controlled trials (and some of them could never be, as in cases where controls would be impractical or unethical to institute). The term randomized controlled clinical trial is an alternative term used in clinical research; however, RCTs are also employed in other research areas, including many of the social sciences.Flowchart of Phases of Parallel Randomized Trial - Modified from CONSORT 2010.png - Wikimedia Commons

Random Sample. A subset of a population chosen in such a way that all samples of the specified size have an equal probability of being selected.

Range. The difference between the highest and lowest scores plus I.

Ratio Scale. A scale that has all the characteristics of an interval scale, plus a true zero point.

Raw Score. A score as it is obtained in an experiment.

Rectangular Distribution. A distribution in which all scores have the same frequency.

Regression Coefficients. The values (point where the regression line intersects the Yaxis) and (slope of the regression line).

Regression Equation. An equation used to predict particular values of for specific values of X. Regression Line. The "line of best fit" that runs through a scatterplot.

Repeated Measures. An experimental design in which more than one dependent-variable measure is taken on each subject.

Sample. A subset of a population.

Sampling Distribution. A theoretical distribution of a statistic based on all possible random samples drawn from the same population; used to determine probabilities.

Sampling Error. The tendency of sample statistics from the same population to vary from one   sample to another.

Scatter plot. The plot of points that results when a distribution of paired X and values are plotted on a graph.   '

Scheffe Test. A method of making all possible comparisons after ANOV A.

Simple Effect. The difference between cell means in a factorial ANOV A.

Simple Frequency Distribution. Scores arranged from highest to lowest, with the frequency of each score placed in a column beside the score.

Skewed Distribution. An asymmetrical distribution. The skew may be positive (more low scores than high, so that the frequency polygon is pointed toward the right) or negative (more high scores than low, so that the frequency polygon is pointed toward the left).

Spearman's Rho. A con-elation statistic for two sets of ranked data.

Standard Deviation. The square root of the mean of the squared deviations.

Standard Error. The standard deviation of a sampling distribution. The standard error (SE) of a statistic (usually an estimate of a parameter) is the standard deviation of its sampling distribution or an estimate of that standard deviation. If the statistic is the sample mean, it is called the standard error of the mean (SEM). The sampling distribution of a mean is generated by repeated sampling from the same population and recording of the sample means obtained. This forms a distribution of different means, and this distribution has its own mean and variance. Mathematically, the variance of the sampling distribution obtained is equal to the variance of the population divided by the sample size. This is because as the sample size increases, sample means cluster more closely around the population mean. Therefore, the relationship between the standard error of the mean and the standard deviation is such that, for a given sample size, the standard error of the mean equals the standard deviation divided by the square root of the sample size. In other words, the standard error of the mean is a measure of the dispersion of sample means around the population mean. In regression analysis, the term "standard error" refers either to the square root of the reduced chi-squared statistic, or the standard error for a particular regression coefficient (as used in, say, confidence intervals). Standard error - Wikipedia             Standard deviation diagram.svg - Wikimedia Commons

Standard Error of Estimate. The standard deviation of the differences between predicted out­ comes and actual outcomes.

Standard Error of the Difference The standard deviation of a sampling distribution of differences between means.

Standard Score. A score expressed in standard-deviation units.

Statistic. Some numerical characteristic of a sample.

Stratified Sample. A sample drawn in such a: way that it reflects exactly a known characteristic of the population.

Subacromial impingement syndrome(SAIS-refers to the inflammation and irritation of the rotator cuff tendons as they pass through the subacromial space, resulting in pain, weakness, and reduced range of motion within the shoulder.

SAIS encompasses a range of pathology including rotator cuff tendinosis, subacromial bursitis, and calcific tendinitis. All these conditions result in an attrition between the coracoacromial arch and the supraspinatus tendon or subacromial bursa.

It occurs most commonly in patients under 25 years, typically in active individuals or in manual professions, and accounts for around 60% of all shoulder pain presentations, making it the most common pathology of the shoulder. https://teachmesurgery.com/orthopaedic/shoulder/subacromial-impingement-syndrome/

Subsample. A subset of a sample.

Sum of Squares. The sum of the squared deviations from the mean; the numerator of the formula for the standard deviation.

t Distribution. Theoretical distribution used to determine significance of experimental results based on small samples.          .

t Test. Significance test that uses the distribution.

Theoretical Distribution. Arrangement of hypothesized scores based on mathematical formulas and logic.

Theoretical Frequency. Number of observations expected in a category if the null hypothesis I is true; expected frequency.

Treatment. A level of an independent variable.

Two- Tailed Test of Significance. Any statistical test in which the critical region is divided into the two tails of the distribution. A two tailed test tells you that you’re finding the area in the middle of a distribution. In other words, your rejection region (the place where you would reject the null hypothesis) is in both tails. For example, let’s say you were running a z test with an alpha level of 5% (0.05). In a one tailed test, the entire 5% would be in a single tail. But with a two tailed test, that 5% is split between the two tails, giving you 2.5% (0.025) in each tail. https://www.statisticshowto.com/two-tailed-test/

Type I Error. Rejection of the null hypothesis when it is true.

Type II Error. Retention of the null hypothesis when it is false.

Upper Limit. The top of the range of values a score from a quantitative variable can take; for example, the number 5 has 5.5 as its upper limit.

U Value. Statistic used in the Mann-Whitney test.

Variability. Differences among scores in a distribution.

Variable. Something that exists in more than one amount or in more than one form.

Variance. The square of the standard deviation.

Wilcoxon and Wilcox Multiple Comparisons. A nonparametric method for independent samples in which all possible pairs of treatments are compared.

Wilcoxon Rank-Sum Test. A nonparametric test for testing the difference between two independent samples.

Wilcoxon Matched-Pairs Signed-Ranks Test. between two correlated samples.

Yates' Correction. A correction for a 2 x 2 chi square when expected frequencies are few.

z Score. A score expressed in standard-deviation units; used to compare the relative standing of scores in two different distributions.

Z line streaming- is observed in muscle damage, as you said, but it's a specific type of muscle damage, damage which originates from the Z-line. The word streaming is used to describe the way by which the Z-lines drift away, slowly degenerating the structure.

Z-line streaming Muscle Damage- High force eccentric muscle contractions can result in delayed onset muscle soreness (DOMS), prolonged loss of muscle strength, decreased range of motion, muscle swelling and an increase of muscle proteins in the blood. At the ultrastructural level Z-line streaming and myofibrillar disruptions have been taken as evidence for muscle damage.