PSYC 203 Study Guide - Midterm Guide: Repeated Measures Design, Effect Size, Type I And Type Ii Errors

• School: Texas A&M University
• Department: Psychology
• Course: PSYC 203
• Professor: Shana Clifford

Document Summary

Null hypothesis significance testing (chapter 9: when we observe events that are very unlikely (i. e less than 5% probability of occurring) under the null, we reject it. In nhst, we calculate the probability (p-value) of obtaining our data if the null hypothesis was true: p-values are widely reported in journal articles. Appropriate use: use when we want to test the difference between a sample mean and the population mean (inferential test, you need: population mean and sd, sample mean and sample size (n) H0 is true (no difference exists between groups) + reject h0 (p < . 05) = type i error (false positive) H0 is false (there really is a difference between groups) + fail to reject h0 (p > . 05) = type ii error (false negative) Independent samples t-test (chapter 11 and lab 5) Homogeneity of variance assumption: the independent samples t-test assumes that variances (sds) are equal in each sample"s population.