Table 4. Frequency Table
Once I had the observed values categorized, I then calculated the mean and standard deviation of this sample set.
With these results I was able to use the assumption that the distribution is normal to calculate the probability that an observed grade point average will fall into each bin. Here are the calculated probabilities.
Now that the probabilities have been calculated and the data categorized, we must check to make sure the expected values in each bin are at least five in order for the goodness-of-fit test to be an very accurate approximation [1]. Table 5 confirms the expected values.
-
Bin
|
Frequency
|
Probability
|
Expected Value
|
1
|
25
|
0.2133
|
18.5571
|
2
|
32
|
0.6628
|
57.6636
|
3
|
30
|
0.3085
|
26.8395
|
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