chapter 8 INDEPENDENT SAMPLES t TEST

two-sample t tests

an inferential statistical test used to compare the mean of one population to the mean of another population

independent-samples t test

an inferential statistical test used to compare two independent samples on an interval- or ratio- level dependent variable

researchers are often willing, for an independent-samples t test, to assume that the dependent variable is ________.

normally distributed

pooled variance

the average variance for two samples

independent samples

the selection of cases for one sample has no impact on the selection of cases for another sample

to calculate the degrees of freedom for an independent-samples t test, subtract _____ from N.

2

paired samples

case selection for one sample is influenced by, depends, on, the cases selected for another sample

in order to use an independent-samples t test to analyze data from two samples, the samples have to be ______ and one needs to know the ______ for each sample.

independent; mean

two different types of two-sample t tests are the ______-samples t test and the _____-samples t test.

independent; paired

to compute either a single-sample z test or a single-sample t test, one must know the population _______.

mean

the numerator in the t equation is the difference between the sample _______.

means

the hypothesis for an independent-samples t test are either directional or ____directional

non

in APA format, _______ means one rejected a null hypothesis with alpha set at .05, and ____ means one failed to reject it.

p < .05; p > .05

if the selection of cases for one sample determines the cases selected for the other sample, then the samples are ________ samples.

paired

the _________ assumption for the independent samples t test is the one that allows a researcher to generalize the results back to the larger population.

random samples

the critical value of t is the border between the ______ and the ______ zones of the sampling distribution of _______.

rare; common; t

if a researcher reports the results of an independent-samples t test as showing a statistically significant difference, the researcher has _______ the null hypothesis.

rejected

two sample t tests use ____ means to draw a conclusion about _____ means.

sample; population