Title: OA 9 Correlation
Course: PSYC 301 Statistical Methods in Psychol > Section: Last Part of Course

This is an assignment of testing correlations.

The data file for this is an old one from a course I taught several years ago. It shows students' GPAs, the total points earned by students across the several exams in the course, and the number of absences the students had. Each line of data is from a single student. The goal here is to determine which of the three variables correlate statistically significantly. That is, for which pairs of variables can we reject a null hypothesis that \(\rho=0\) ?

Follow these steps to use jamovi on your computer to do the assignment. Below that are questions about the work you did to submit for the assignment.

1. Download this data file and open it in jamovi: Absences.omv
2. Select the Analyses tab
3. Select the Regression icon (4th from left) and in the drop down select 'Correlation Matrix'.
4. In the left hand box of the left hand window are three variables to select and move to the right hand box in the left hand window.
5. Make sure the following are marked/checked.
  - Pearson is checked under Correlation Coefficients
  - Report significance and N are checked under Additional Options
  - Correlated is marked under Hypothesis (that is for two-tailed testing)
  - Nothing is checked under Plot (the outputs are too confusing to try to describe here)
6. Write down the correlation value for each pair of variables and the p-values for each correlation.

Answer these questions in the text entry box for this assignment.

1. There are three variables, which means there are three correlations reported (one for each pairing of the variables; usually referred to as pairwise correlations). Clearly indicate in your answer the correlations that were calculated along with the variables for which each correlation was calculated.
2. Which of the three correlations were large enough to reject the null hypothesis, and which were not large enough to reject the null hypothesis?
3. Describe the meaning of each of those three decisions to reject or retain the null hypothesis.