PSC 41 Lecture Notes - Lecture 15: Statistical Inference, Type I And Type Ii Errors, Null Hypothesis

• School: UC-Davis
• Department: Psychology
• Course: PSC 41
• Professor: Cross, Victoria

Document Summary

Lecture 15 inferential statistics conceptual introduction. Hypothesis testing: identify the differences that are not due to chance, take random effects (chance) into account. Decision making: type i and type ii errors, power and effect size. Inferential statistics give us an objective measure of the probability that any observed difference is due to chance. Make inferences to a population from sample data: population: a group of people (or other animals, or plants etc. ) who share certain characteristics. Also known as: research hypothesis, experimental hypothesis, working hypothesis, alternate hypothesis (when compared to the null hypothesis) The independent variable does not cause a difference. The mean of one group is the same as the mean of the other group. Non-directional (two-tailed) hypothesis: states that there will be a difference without specifying which direction, h1: m1 m2. Directional (one-tailed) hypothesis: specifies which side, h2: m1 > m2 or h3: m1 < m2.