THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION

Multiple Choice

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
From a random sample of ten students in an operations management class that uses group-learning techniques,the mean examination score was found to be 82.75 and the sample standard deviation was 3.24.For an independent random sample of eight students in another marketing research class that does not use group-learning techniques,the sample mean and standard deviation of exam scores were 75.62 and 7.27,respectively.It is assumed that the and unknown population variances are not assumed to be equal.
-Determine the number of degrees of freedom.

A) 10
B) 15
C) 20
D) 25