In: Statistics and Probability
Part 2
Consider the following data set:
Republican |
Democrat |
Independent |
Total |
|
Supports the death penalty |
120 |
103 |
18 |
|
Opposes the death penalty |
70 |
57 |
20 |
|
Does not know/Not sure |
45 |
24 |
11 |
|
Total |
(e) Interpret the p-value. Be sure to answer the research question.
(a) The completed is as below
Observed | ||||
Republican | Democrat | Independent | Total | |
Supports | 120 | 103 | 18 | 241 |
Opposes | 70 | 57 | 20 | 147 |
Not Sure | 45 | 24 | 11 | 80 |
Total | 235 | 184 | 49 | 468 |
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(b) The Expected value data are in the table below. Each Cell = Row total * Column Total/N. N = 468
The degrees of freedom, df = (r – 1) * (c -1) = (3 - 1) * (3 - 1) = 4
Expected | ||||
Republican | Democrat | Independent | Total | |
Supports | 121.015 | 94.752 | 25.233 | 241 |
Opposes | 73.814 | 57.795 | 15.391 | 147 |
Not Sure | 40.171 | 31.453 | 8.376 | 80 |
Total | 235 | 184 | 49 | 468 |
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(c) The Hypothesis:
H0: There is no association between political party and stand on the death penalty. They are independent.
Ha: There is a relation between political party and stand on the death penalty. They are dependent.
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(d) The Test Statistic: The table below gives the calculation of .
# | Observed | Expected | (O-E) | (O-E)2 | (O-E)2/E |
1 | 120 | 121.015 | -1.015 | 1.030225 | 0.0085 |
2 | 70 | 73.814 | -3.8141 | 14.54736 | 0.1971 |
3 | 45 | 40.171 | 4.8291 | 23.32021 | 0.5805 |
4 | 103 | 94.752 | 8.2479 | 68.02785 | 0.7180 |
5 | 57 | 57.795 | -0.7949 | 0.631866 | 0.0109 |
6 | 24 | 31.453 | -7.453 | 55.54721 | 1.7660 |
7 | 18 | 25.233 | -7.2329 | 52.31484 | 2.0733 |
8 | 20 | 15.391 | 4.609 | 21.24288 | 1.3802 |
9 | 11 | 8.376 | 2.6239 | 6.884851 | 0.8220 |
Total | 7.557 |
test = 7.56
The p value: The p value at test = 7.56, df = 3; P value = 0.1091
The Decision Rule: If p value is < 0.05 (the default level), Then Reject H0.
The Decision: Since p value is > 0.05, Fail to Reject H0.
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(e) The probability of finding a test statistic as great as or greater than 7.56 Assuming that the null hypothesis is true is 0.1091, which is very high and therefore we fail to reject the null hypothesis.
There isn't sufficient evidence at the 95% level of significance to warrant rejection of the claim that there is a relation between political party and stand on the death penalty.
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