Homework Assignment #5
Name: _____________________________________________________
Professor was concerned about the extent to which his students were benefiting from the various activities involved in his course. After the final grades were assigned, he was quite lucky to obtain reliable information about the studying habits of all his students. As it turned out, all 40 of the students could be classified in one of four groups. Students in group A never attended the lectures and never showed up for any laboratory exercises or office hours. Students in group B attended only the lectures, whereas students in group C attended the lectures and the labs. Finally, students in group D attended all lectures and labs and often showed up during office hours. The final grades of the students in the four groups were as follows:
A: 70, 50, 70, 60, 40, 60, 40, 50, 90, 60
B: 60, 60, 70, 50, 50, 70, 40, 80, 70, 90
C: 60, 80, 80, 90, 70, 100, 70, 80, 100, 50
D: 100, 90, 70, 80, 60, 80, 70, 90, 70, 80
Using a statistical computer program of your choice, you are expected to obtain answers to the following questions:
1) What are the means and standard deviations of each of the four groups?
2) What is the value (and degrees of freedom) of the F statistic to test the hypothesis that studying habits affect the final grades in a course?
3) What is the probability associated with the F value under the null hypothesis?
4) Is there a significant effect of studying habits on the final grades? Why?
5) Can we say that a student’s chance to obtain a good grade is higher if he/she often shows up during office hours? Why?
