PSYCH 100A Lecture Notes - Lecture 9: Repeated Measures Design, Null Hypothesis, Standard Deviation
Document Summary
Useful for comparing 2+ sets of data: independent-measures (between-subjects) Obtain data from two completely different samples. Example: compare men and women: repeated-measures (within-subjects) Hypotheses: h0: or (no difference between means, h1: or (difference between means) Remember: compares difference between two sample means. But we generally hypothesize that , so. With df = n-2, with n=total number of data points with groups combined: n = n1 + n2, df = n-2. Used when you don"t have equal group sizes: so that the variance isn"t weighted by the population size differences. Research question: do high school students who regularly watched sesame. Street get better grades: h0, h1: t = 4. 00. Since t = 4. 00, and the p-value < . 05, we reject the null hypothesis. We conclude that, on average, there is a significant difference between the high school grades for students who watched sesame street and those who did not.
