1. Hanh has developed a standardized test for measuring attention span for adults in general population. The scores on the test form a normal distribution with = 60 and = 10. Hanh would like to use this test to investigate heavy adult smokers have different attention span than those in general population. A sample of n = 25 heavy smokers is obtained and the mean attention span score for this sample is M = 60. Based on this sample, is the attention span for heavy smokers are significantly different from those of the general population at = 0.01? Report with Cohen's d