In: Statistics and Probability
Questions 14 through 18 refer to the following:
The following table is a summary of randomly chosen student evaluations of faculty at a university over a three-year period. The researcher is interested in whether the distribution of evaluations differs by faculty rank.
Rank |
||||
Evaluation |
Assistant Professor |
Associate Professor |
Professor |
Total |
Above Average |
44 |
39 |
36 |
119 |
Below Average |
36 |
31 |
54 |
121 |
Total |
80 |
70 |
90 |
240 |
question 14 If faculty rank and evaluation are independent, how many assistant professors would have been expected to receive above average evaluations?
1 points
Question 15
What's the value of the test statistic?
1 points
Question 16
What's the critical value if the significance level is .05?
1 points
Question 17
What's the p-value (any value in your range if you used a table)?
1 points
Question 18
Do the data provide significant evidence at the .05 level that faculty rank and evaluation are dependent?
yes |
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no |
||
socks |
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light bulb |
14:
The required expected value is
15:
Here we need to use chi square test. Following is the output of chi square test:
Chi-square Contingency Table Test for Independence | ||||||
Assistant Professor | Associate Professor | Professor | Total | |||
Above Average | Observed | 44 | 39 | 36 | 119 | |
Expected | 39.67 | 34.71 | 44.63 | 119.00 | ||
Below Average | Observed | 36 | 31 | 54 | 121 | |
Expected | 40.33 | 35.29 | 45.38 | 121.00 | ||
Total | Observed | 80 | 70 | 90 | 240 | |
Expected | 80.00 | 70.00 | 90.00 | 240.00 | ||
5.30 | chi-square | |||||
2 | df | |||||
.0707 | p-value |
The test statistics is
16:
Degree of freedom: df =( number of rows -1)*(number of columns-1) = (2-1)*(3-1)=2
The critical value of test statistics using excel function "=CHIINV(0.05,2)" is 5.991
17:
The p-value using excel function "=CHIDIST(5.3,2)" is: 0.0707
18:
Since p-value is greater than 0.05 so we cannot conclude that the data provide significant evidence at the .05 level that faculty rank and evaluation are dependent.