Reference no: EM131954550

A sports psychologist wanted to find out whether there is a relationship between drinking coffee and speed in running a 5 k run. He recorded the time (in minutes) of 5 coffee drinkers competing in the marathon as follows: 27, 25, 23, 24, 26, and 5 non- coffee drinkers also competing in the same marathon as follows: 28, 24, 13, 21, 20. Convert these data into a form suitable for the point-biserial correlation, and assign a score of 0 to the non-coffee drinkers and a 1 to the coffee drinkers. A) Compute the point biserial correlation , and B) compute the coefficient of determination (r2) and describe how much of the variability in marathon speed is determined by its association with drinking coffee.