Inferential Statistics - CPY 511
The two independent samples t - test
Describe the t distribution. State how the shape of the curve and the tails differ from a normal distribution when df is small.
Describe how the t distribution for small df differs from the t distribution for larger df.
Explain what happens to the t distribution when df goes over 120.
Explain the logic of a hypothesis test. Describe the rejection and non-rejection regions.
Explain the purpose of the critical value in a hypothesis test.
Explain
when the researcher rejects the null hypothesis in terms of the
observed value, the critical value and the regions for the test.
Explain what the researcher uses as the basis for rejecting the null hypothesis in terms of the observed probability.
State what a two independent samples t test is used to compare.
List the assumptions underlying the legitimate use of the two independent samples t test.
Define the inferential variance.
Name
the best estimators of the population variance for the two independent
samples t test with equal sample sizes and with unequal sample sizes.
Explain why it is important to understand the formula for the SE.
Explain
what happens to the SE when the population variance changes, when the
sample variance changes, and when the sample size changes.
Explain what happens to t observed when the IV effect changes and when the SE changes.
Explain the relationship between the size of t observed and the size of p observed.