Question

A professor in the Business department wants to know if there is a significant difference in the performance on the first exam between two different classes. One class meets in the morning while the other meets at night. The results of this test are listed below along with an excel analysis conducted at the 5% significance level (α=0.05).

t-Test: Two-Sample Assuming Equal Variances
	8 am Class	7 pm Class
Sample Mean	80.471	76.846
Sample Variance	97.51	162.14
Sample Observations	17	13
Pooled Variance	125.21
Hypothesized Mean Difference	0
df	28
t Stat (t*)	0.879
P(T<=t) one-tail	0.1934
t Critical one-tail	1.701
P(T<=t) two-tail	0.3868
t Critical two-tail	2.048

Based on the output given above, what are the decision and conclusions for the test, conducted at the 5% significance level?

Group of answer choices

Reject the null hypothesis; conclude there is difference between the grades of the morning class and the grades of the evening class.

None of above

Fail to reject the null hypothesis, conclude there is insufficient information to decide there is no difference between the grades of the morning class and the grades of the evening class.

Reject the null hypothesis; conclude there is no difference between the grades of the morning class and the grades of the evening class.

Fail to reject the null hypothesis, conclude there is insufficient information to decide there is difference between the grades of the morning class and the grades of the evening class.

Answer 1

This is a two tailed test

alpha = 0.05

From the given table ,

Critical value = +/- 2.048

Reject H0 if t < -2.048 or t > 2.048

test statistic = 0.879

Fail to reject the null hypothesis, conclude there is insufficient information to decide there is difference between the grades of the morning class and the grades of the evening class.