From a random sample of 7 students in an introductory finance class that uses group-learning techniques, the mean examination score was found to be 77.94 and the sample standard deviation was 2.7. For an independent random sample of 8 students in another introductory finance class that does not use group-learning techniques, the sample mean and standard deviation of exam scores were 73.62 and 8.7, respectively. Estimate with 90% confidence the difference between the two population mean scores; do not assume equal population variances. E Click the icon to view the Student's t distribution table. The 90% confidence interval is from a lower limit of to an upper limit of (Round to two decimal places as needed.)