You continue to explore your data because you have found an additional variable of interest (the 'bedtime' that the participants slept at). You run a Pearson correlation to see whether there is a relationship between sleep duration and actual bedtime. It turns out that your result is in the expected direction, with your r valuedisplaying a significant moderate negative correlation.You are glad that the result makes sense and fits your expectation, however you would like to report the variance explained by the relationship.

Correlations Mean Mean TST Bedtime (school (school nights) nights) Mean TST (school nights) Pearson Correlation -.493 Sig. (2-tailed) 000 N 213 212 Mean Bedtime (school Pearson Correlation -.493 nights) Sig. (2-tailed) 000 N 212 212 ** Correlation is significant at the 0.01 level (2-tailed)