DrJirandi Is Studying the Effects of Caffeine on Road Rage

Multiple Choice

Dr.Jirandi is studying the effects of caffeine on road rage.He randomly gives half of his participants an espresso every morning for one month before their commute to work,while the other half consumes a decaffeinated coffee.After the daily commute,each participant provides a rating of how angry they felt during the drive,and stress levels are measured by taking a saliva sample.If Dr.Jirandi wanted to determine whether the caffeine group had significantly more road rage than the decaffeinated group,which of the following pieces of information would he NOT need to know?

A) the number of participants in each group
B) the mean anger ratings and levels of stress hormones of each group
C) the standard deviation for anger ratings and stress hormone levels of each group
D) the correlation coefficient of each group