Research & Statistics Flashcards
Heteroscedasticity
Heteroscedasticity (the violation of homoscedasticity) is present when the size of the error term differs across values of an independent variable.
In a scatterplot, unequal variability of “Y” scores at different values of “X.”
Homoscadasticity
Homoscedasticity describes a situation in which the error term (that is, the “noise” or random disturbance in the relationship between the independent variables and the dependent variable) is the same across all values of the independent variables.
Inferential statistics
Procedures that allow us to infer the values of populations using samples from that population.
Cross-validation
Cross-validation refers to reassessing test’s criterion validity with a new sample. Because of the chance factor operating in the original study are not all present to those operating in the cross-validation summary, the validity criterion usually shrinks (is smaller) for the new sample.
Associated with Shrinkage
ANCOVA`
The ANCOVA is a version of the ANOVA that is used to increase the efficiency of the analysis by statistically removing variability in the DV that is due to an extraneous variable. When using the ANCOVA, each person’s score on the DV is adjusted on the basis of his or her score on the extraneous variable.
Central limit theorm
The Central Limit Theorem is derived from probability theory and predicts that the sampling distribution of the mean (a) will approach a normal shape as the sample size increases, regardless of the shape of the population distribution of scores; (b) has a mean equal to the population mean; and (c) has a standard deviation equal to the population standard deviation divided by the square root of the sample size. This standard deviation is referred to as the standard error of the mean.
Coefficient of equivalence
reliability establishing of alternate forms of a test by administering the forms at the same time
Coefficient of equivalence and stability
reliability establishing of alternate forms of a test by administering the forms at the different times
Classical test theory
The theory of measurement that regards observed variability in test scores as reflecting two components: true differences between examinees on the attribute(s) measured by the test and the effects of measurement (random) error.
Coefficient alpha / KR-20
Method for assessing internal consistency reliability that provides an index of average inter-item consistency. Kuder-Richardson Formula 20 (KR-20) can be used as a substitute for coefficient alpha when test items are scored dichotomously.
