The paper describes a study that investigated the relationship between depression and chocolate consumption. Assume that 931 study participants were divided into 311 who screened positive for depression and 620 who did not screen positive. The mean number of servings of chocolate for the sample of people that screened positive for depression was 8.39 servings per month and the sample standard deviation was 14.83. For the sample of people who did not screen positive for depression, the mean number of servings per month was 5.39 and the standard deviation was 8.76. Estimate the difference in the mean of people who screened positive for depression and the mean of people who did not screen positive for depression using 90% confidence interval.