Chapter 9: Effect Size and NHST: One-Sample Designs

alpha

α; probability of type I error

alternative hypothesis

hypothesis about population parameters that is accepted if the null hypothesis is rejected

beta

probability of making a type II error

critical value

number from a sampling distribution that determines whether the null hypothesis is rejected

NS

a difference that is not statistically significant

null hypothesis

hypothesis about a population or the relationship among populations

null hypothesis significance testing

process that produces probabilities that are accurate when the null hypothesis is true

one sample t test

statistical test of the hypothesis that a sample with mean X-bar came from a population with a mean mu.

one-tailed test of significance

statistical test that can detect a positive difference in population means or a negative difference, but not both

rejection region

area of a sampling distribution that corresponds to test statistic values that lead to rejection of the null hypothesis

significance level

probability chosen as the criterion for rejecting the null hypothesis

statistically significant

difference so large that chance is not a plausible explanation for the difference

two-tailed test of significance

statistical test for a difference in population means that can detect positive and negative differences

Type I error (alpha)

rejection of a null hypothesis that is true

Type II error (beta)

failing to reject a false null hypothesis