You are testing the claim that the mean GPA of night students is greater than the mean GPA of day students.

-Sample 1: You sample 20 night students, and the sample mean GPA is 2.61 with population standard deviation of 0.74

-Sample 2: You sample 60 day students, and the sample mean GPA is 2.8 with population standard deviation of 0.86

Calculate the z-test statistic, please keep at least 6 decimal places during the calculation.

Hint: Use the test statistic formula: z=(x1x2)(12)21n1+22n2

, (Note: 12 = 0)