Definitions Flashcards
Null distribution
The sampling distribution that would exist if the null hypothesis were true
Type one error
Occurs when we reject the null hypothesis but the null hypothesis is actually true. Analogous to Alpha
Alpha
The probability that our observed result or something more extreme, given our null hypothesis is true.
Type two error
When we fail to reject the null hypothesis but the null is actually false. Analogous to Beta
Beta
The probability of a type 2 error
Power
The probability we will reject the null hypothesis and the null hypothesis is actually false.
Test statistic
A value calculated on a sample that is compared to a critical value in order to make a decision about the null. The test statistic has a distribution under the null. Ex ND, T-distribution, F-distribution
T-test for independent samples Means
A test used when we are interested in the null hypothesis that two samples were drawn from populations with identical means.
Analysis of variance (ANOVA)
A test statistic used when we are interested in the null hypothesis that two or more samples were drawn from population with identical means. Most experiments.
Effect size
The size of the observed effect of the IV on the DV.
Pearson r
A measure of the linear correlation between two variables.
Cohen’s d
A measure of the difference between samples means adjusted for the variability within each of two groups.
Eta squared
A measure of the correlation between two variables. It is not necessary for the variables to be linearly related.
N^2=ssbetween/sstotal
Confidence interval on sample mean
A range of values so defined that there is a specified probability that the value of a population mean lies within it. E.G., 95% confidence interval for the sample mean.
