Chapter 9: The Single-Sample t Test and the Paired-Samples t test

t distributions

used when we do not know the population standard deviation and are comparing only two groups.

single-sample t test

A hypothesis test in which we compare data from one sample to a population for which we know the mean but not the standard deviation.

degrees of freedom

is the number of scores that are free to vary when estimating a population parameter from a sample. determined by "df=(N-1)"

t statistic

the distance of a sample mean from a population mean in terms of the estimated standard error.

paired-samples t test

{also called dependent-samples t test} Used to compare two means for a within-groups design, a situation in which every participants is in both samples. We use this test when we have all data for all participants under two conditions.