Z = (mean1 - mean2)/standard error (SE) of difference between means
SEdiff = √(SEmean1^2 + SEmean2^2)
SEm = SD/√n
If only one SD is provided, you can use just that to determine SEdiff.
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability
of the Z score.
You are testing the claim that the mean GPA of night students is less than the mean GPA of day students.
You sample 45 night students, and the sample mean GPA is 2.18 with a standard deviation of 0.31
You sample 30 day students, and the sample mean GPA is 1.97 with a standard deviation of 0.71
Calculate the test statistic, rounded to 2 decimal places
2 answers
6.78