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Thorne and Giesen Book Cover
Statistics for the Behavioral Sciences, 4/e
Michael Thorne, Mississippi State University -- Mississippi State
Martin Giesen, Mississippi State University -- Mississippi State

Significance of the Difference Between Two Sample Means

Definitions


independent t test  test for situations in which two separate and independent groups are compared
control group  group of subjects not subjected to experimental treatment, but like the experimental group in all other ways
independent sample  sample in which the behavior of the members is not related to the behavior of members of another sample
sampling distribution of the mean differences  distribution whose scores are differences between pairs of sample means
standard error of the difference between means  standard deviation of the sampling distribution of the mean differences
estimated standard error of the mean differences  estimated standard deviation of the sampling distribution of the differences
two-tailed test  significance test that considers both ends of the distribution
one-tailed test  significance test that only considers the end of the distribution predicted by the experimenter
homogeneity of variance  condition in which the population variances are the same
robustness of a test  the property of a statistical test to give valid conclusions even when its assumptions are violated
matched pairs  dependent samples in which subject pairs are as closely matched as possible on some characteristic(s) relevant to the dependent variable
within-subjects comparison  the same individuals are subjected to each of two treatment conditions
repeated measures design  experimental design in which each subject experiences all levels of the independent variable; also known as a within-subjects design
counterbalancing  method to control for order effects in a repeated measures design by including all orders of treatment presentation
double-blind  experimental design in which neither the participant nor the treatment administrator knows the participant's group designation