posted by GG on .
The Computer Anxiety Rating Scale (CARS) measures an individuals level of computer
anxiety, on a scale from 20 (no anxiety) to 100 (highest level of anxiety). Researchers
at Miami University administered CARS to 172 business students. One of the objectives
of the study was to determine whether there are differences in the amount of computer
anxiety experienced by students with different majors. They found the following.
Source Degree of freedom Sum of Square Mean Square(Variance) F
Among majors 5 3,172
Within majors 166 21,246
Total 171 24,418
Major n Mean
Marketing 19 44.37
Management 11 43.18
Other 14 42.21
Finance 45 41.80
Accountancy 36 37.56
MIS 47 32.21
(a). Complete the ANOVA summary table
(b). At 0.05 level of significance, is there evidence of difference in the
mean computer anxiety experienced by different majors?
(c). If the results in (b) indicate that it is appropriate, use the Tukey-Kramer
procedure to determine which majors differ in mean computer anxiety. Discuss your
Your ANOVA summary table should have the following setup:
Fill in the data with what you know, then find what you don't know.
Here are a few hints:
SS total = SS between + SS within
To calculate df between:
k - 1
Note: k = number of levels or groups.
To calculate df within:
N - k
Note: N = total number of values in all levels or groups.
df total = df between + df within
To calculate MS between:
SS between/df between
To calculate MS within:
SS within/df within
To calculate F-ratio:
MS between/MS within
After filling in the table and finding the F-ratio, find the critical or cutoff value to reject the null using an F-table. Compare to the F-ratio to determine whether or not to reject the null. If the null is rejected, there is a difference. If the null is not rejected, there is no difference.
If you need to use the Tukey procedure, compare all possible pairs of means to determine which majors differ.
I hope this brief summary will get you started.