PSY 3213L Lecture Notes - Lecture 13: Null Hypothesis, Statistical Hypothesis Testing, Confidence Interval

• School: University of Florida
• Department: Psychology
• Course: PSY 3213L
• Professor: Melissa Cervantez

Document Summary

Factorial desging with two or more independent variables has been used. Systematic variance deviation of the groups means from grand mean respective group means: calculating effect size, cohen"s d- effect size estimate used when comparing two means, confidence intervals. Signifcance level: researchers traditionally used a . 05 or a . 01 significance level in the decision to reject the null hypothesis. Specifies the probability of a type i error if the null hypothesis is rejected: significance level chosen and the consequences of a type i or a type ii error are determined by the use of the results. Smaller effect sizes require larger samples to be significant at the . 05 level: higher desired power demands a greater sample size, researchers usually strive power between . 7-. 9 to determine sample size. Importance of replications: scientists attach little importance to the results of a single study, detailed understanding requires numerous studies examining same variables, researchers look at the results of studies that replicate previous investigations.