In: Statistics and Probability
Grades and AM/PM Section of Stats: There were two large sections of statistics this term at State College, an 8:00 (AM) section and a 1:30 (PM) section. The final grades for both sections are depicted in the contingency table below.
Observed Frequencies: Oi's
A | B | C | D | F | Totals | |
AM | 6 | 11 | 19 | 20 | 15 | 71 |
PM | 19 | 19 | 19 | 13 | 7 | 77 |
Totals | 25 | 30 | 38 | 33 | 22 | 148 |
The Test: Test for a significant dependent
relationship between grades and the section of the course. Conduct
this test at the 0.05 significance level.
(a) What is the test statistic? Round your answer to 3 decimal places.
χ2
=
(b) What is the conclusion regarding the null hypothesis?
reject H0fail to reject H0
(c) Choose the appropriate concluding statement.
We have proven that grades and section of the course are independent.
The evidence suggests that there is a significant dependent relationship between grades and the section of the course.
There is not enough evidence to conclude that there is a significant dependent relationship between grades and the section of the course.
Solution:
a) Test statistic X²= 13.066
b) X²=13.066 > X²c=9.488, Hence we reject Ho.
c) conclusion:
The evidence suggests that there is a significant dependent relationship between grades and the section of the course.
Calculation: