I have a group of 8 subjects. For each subject I measure their heart rate 30,20, and 10 min before and after they take a drug. I then average the heart rate measurements in each subject to get one value for before and after the drug was taken. As a result, I have 8 before and 8 after averaged heart rate values. I want to compare whether there is a difference in heart rate after the drug was taken. What test would be recommended in this scenario?
I currently use JMP software and conducted an ANOVA on the groups using 'fit Y by X' and received an F value of 0.157. However, when I blocked by the subjects, and used the 'Fit Model' option, the F value was 0.035. If I blocked by subject and used the 'fit Y by X' and conducted an ANOVA, this also yielded significance. One method returned a significant result while the other did not. Why is this? Which is correct? Is it correct to block in this scenario? Also, which statistical test should I use?