A statistics professor wishes to estimate the average mark on a term test for a course that has multiple sections and many students. A survey of some of the students registered for the course reveals the following results:

Descriptive statistics
	Class Grades
count	32
mean	70.81
sample variance	520.15
sample standard deviation	22.81
minimum	14.3
maximum	99.2
range	84.9
standard error of the mean	4.03

The student from the course wonders whether the population mean could have been 75 or 80.

Select one:

a. Since 80 is not within the 95% confidence interval, the population mean is not likely to be 80.

b. Since neither 75 nor 80 is within the 95% confidence interval, the population mean is not likely to be 75 or 80.

c. Since 80 is within the 95% confidence interval, the population mean is likely to be 80.

d. Since 80 is not within the 95% confidence interval, the population mean is not likely to be 80, but it is likely to be 75.

e. Since 75 is within the 95% confidence interval, the population mean is likely to be 75.