PSYCH 100A Chapter Notes - Chapter 9: Type I And Type Ii Errors, Null Hypothesis, Statistical Inference
Document Summary
Descriptive statistics: the science of describing distributions of samples or populations. Inferential statistics: science of drawing some conclusion or inference about a population parameter on the basis of a sample statistic. E. g. confidence intervals, point estimates (using sample mean to estimate population mean) Hypothesis evaluation: deciding whether inferences about populations and their parameters should be rejected or not rejected. Hypothesis: assumption or inference about a parameter or distribution that can be tested. It is easier to prove a statemetn false that it is to prove it true. We can conclude with confidence that a hypothesis is false but that does not necessarily mean that the hypothesis is really false. Support for a hypothesis is acquired by rejection of a contradictory hypothesis. Null hypothesis (h0): hypothesis that there is no effect or no difference. Alternative hypothesis (h1): hypothesis that there is in fact an effect or a difference. Null and alternative hypotheses must be mutually exclusive.
