From a random sample of seven students in a marketing research class
that uses group-learning techniques, the mean examination score was found to be 78.25 and the sample standard deviation was 2.87. For an independent random sample of ten students in another marketing research class that does not use group-learning techniques, the sample mean and standard deviation of exam scores were 74.94 and 9.15, respectively. Estimate with 95% confidence the difference between the two population mean scores. Do not assume equal population variances.