Question

Question 8 3 pts Small Sample Difference of Means Test. Each year Forbes puts out data on the top college and universities in the U.S. The following is a sample from the top 300 institutions in 2015. The test we will look at is the difference in the average 4-year graduation rates of private and public schools. The data are given below. We can assume equal variances. Note: I used the variances for all my calculations. 4-year graduation rates by Public and Private status of Top Universities Private STEM Public STEM Leaf Mean Median Min Max Variance Std Deviation су Count Private 70.526 69.000 49.000 87.000 139.374 11.806 16.739 19 Public 57.294 61.000 32.000 86.000 197.346 14.048 24.519 17 Leaf 2 3 49 5 689 6011789 7459 80 244 77 31278 49 s1129 61 245 558 72 86 9 A value of 49 is an rate of 49% A value of 32 sasto If a priori we thought private schools should have a higher 4-year average graduation rate than public schools, the alternative hypothesis for this problem would be Hamu(private) - mu(public) = 0 Ha: mu(private) - mu(public) > 0 Ha: mu(private) - mu(public) NEO Ha: mu(private) - mu(public) < 0

Answer 1

If a priori we thought that private schools have a higher 4-year average graduation rate than public schools, then this is the claim that we want to prove to be true. So our alternate hypothesis should be that this claim isn't true.

The null hypothesis is a statement about the population that is believed to be true, unless proven otherwise. The alternate hypothesis, is contradictory to the null hypothesis. So,

or