Statistical Tests- Errors and other Rules Flashcards
What is a type 1 error?
When the null hypothesis is rejected and the alternative hypothesis is accepted when the null hypothesis is ‘true’.
What is a type 1 error also called?
The error of optimists
When does a type 1 error occur?
The significance level is too lenient (p<_10)
What is a type 2 error?
The null hypothesis is accepted but should have been rejected as the alternative hypothesis is ‘true’.
What is a type 2 error also called?
The error of pessimists.
When does a type 2 error occur?
The significance level is too stringent (p<_0.01)
What is a contingency table?
A table which shows all the possible outcomes of a study.
In a contingency table chi-squared is used to calculate?
The degrees of freedom.
How do you calculate chi-squared on a contingency table?
(number of rows - 1) x (number of columns - 1)
What are not included when calculating the number of rows/columns?
Titles and the ‘total’ rows/columns
For a sign test and Wilcoxon if there is no difference between the 2 conditions what happens?
The participant is ignored and the removed from N.
In a Wilcoxon if a matched pairs design has been used what happens?
N= number of pairs rather than participants in total.
