A researcher investigates whether or not a new cold medication disrupts mental alertness. It is known that scores on a standardized test containing a variety of problem-solving tasks are normally distributed with μ = 64 and σ = 8. A random sample of n = 16 subjects are given the drug and then tested. For this sample, the mean is M = 58, and the standard deviation is s = 7. (4 pts) 1) Are the data sufficient to conclude that the medication affects performance? Test with α = .01.

2) Compute Cohen's d to measure the size of the treatment effect.