Question

Dr. Rueckert would like to determine whether the time and day a class is held at NEIU makes a difference in how much students learn.  To study this, she decides to compare three different SRM II classes:  one held at 9:25 am on Tuesdays and Thursdays, one held at 5:40 pm on Tuesdays and Thursdays, and one held at 8 am on Saturday.  At the end of the semester, she gives a test of statistical concepts to all 3 classes. Another professor points out a flaw in Dr. Rueckert’s study.  Since she did not randomly assign the students to the class, it is possible that the difference in scores is not due to one class learning more than another.  Maybe the students in the classes differed in their knowledge of statistics before the class even began.  Since students have to take classes that fit into their schedules, it’s not possible to randomly assign them to classes.  Describe another study that could be done to control for this.  It must be a mixed factorial design.  The study must determine whether students in classes that are held at different times of the day differ in knowledge before the class even starts, and whether they differ in the increase in knowledge gained as a result of taking the class. Please use the bolded part to answer the questions.

A.  What will be the dependent variable?

B.  What will be the independent variables?

C.  For each independent variable:

C1.  What are the levels?

C2.  Is it between or within-subjects?

D.  What are your null hypotheses?

E.  What are some possible confounding variables or other problems you can anticipate, and how would you attempt to control for them?

F.  If the students who take night and Saturday classes know more about statistics before they even take the class, which null hypotheses would you reject?  Why?

G.  If the students actually learn more about statistics in classes held in the evening or Saturday, which null hypotheses would you reject?  Why?

Answer 1

there must be a test conducted before the start of class to know the prior knowledge of the students and difference between the test conducted after completion of the session and the one before will indicate knowledge gained by the students. the course and teacher conducting the course must be the same to understand actaual relation between knowledge gained by students and slot in which they study

a) dependent variable: score of the test.

b) independent variable: time-day slot in which they attend class.

c) there is only one independent variable time-day slot in which they attend class taken as factors. they may be regarded as 3 dummy variables. there are no levels in it

d) null hypothesis: the time and day a class is held at NEIU does not make a difference in how much students learn. Rejecting null hypothesis would mean there is significant difference.

H01: 9:25 am on Tuesdays and Thursdays classes are not significant for students to learn

H02: 5:40 pm on Tuesdays and Thursdays classes are not significant for students to learn

H03: 8 am on Saturday classes are not significant for students to learn

e) other factors that may affect the study are:

if teacher is different in each slot, teacher knowledge would play a role. also teacher style of teaching will vary in this case. hence there must be a same teacher in both the classes

the duration(total study hours) and structure of the course must be same for all the 3 slots.

f) in this case this effect needs to be adjusted in the study. otherwise it may indicate false results of rejecting that the effect of night and saturday classes are not significant (as they already know about the subject they are likely to score well in test).

g)  If the students actually learn more about statistics in classes held in the evening or Saturday, hypothesis that evening or saturday classes are not significant will be rejected