Lecture 10: Research Questions for Group Differences V (NHST) Flashcards
What is a null hypothesis?
A hypothesis proposed about the value of the population parameter relevant to the research question being asked, and is presumed to be true.
What is an alternative hypothesis?
Opposite to the null hypothesis.
What is a criterion?
A criteria set a priori to reject or not reject the null hypothesis, usually referred to as a.
What is a p-value?
The conditional probability of the sample effect size being observed or one larger, given that the null hypothesis is true.
What is the alpha value?
The conditional probability of rejecting the null hypothesis when it is in fact true.
What happens if the p-value is smaller than a?
We reject the null hypothesis.
Why do we set an alpha value?
To enable us to know the maximum chance of falsely rejecting a true null hypothesis.
What is a type 1 error?
Falsely rejecting a true null hypothesis.
What is a type 2 error?
Not rejecting a false null hypothesis.
What does the accuracy of the p-value depend on?
A set of statistical assumptions and other research design assumptions (e.g. reliability)
What is a p-value function plot?
A graph of the observed p-value against the null hypothesised p-value.
What is a confidence interval?
The complete set of null hypothesised values that would not be rejected if used in a NHST test on the sample statistic (gives more information than p-values)
