In: Statistics and Probability
Please clearly state the step number next to the answers given, thank you!
A political researcher wishes to know if political affiliation
and age are related. He has collected data on 283 persons in three
age categories. Is there evidence that age and political
affiliation are related?
Age | Democrat | Republican | Independent | Total |
---|---|---|---|---|
18-31 | 37 | 38 | 19 | 94 |
32-51 | 43 | 38 | 23 | 104 |
52-68 | 32 | 35 | 18 | 85 |
Total | 112 | 111 | 60 | 283 |
Step 1 of 8: State the null and alternative
hypothesis.
H0: political affiliation and age are dependent
Ha: political affiliation and age are independent
OR
H0: political affiliation and age are independent
Ha: political affiliation and age are dependent
Step 2 of 8: Find the expected value for the
number of democrats that are 18-31 years old. Round your answer to
one decimal place.
Step 3 of 8: Find the expected value for the
number of republicans that are 32-51 years old. Round your answer
to one decimal place.
Step 4 of 8: Find the value of the test statistic.
Round your answer to three decimal places.
Step 5 of 8: Find the degrees of freedom
associated with the test statistic for this problem.
Step 6 of 8: Find the critical value of the test
at the 0.005 level of significance. Round your answer to
three decimal places.
Step 7 of 8: Make the decision to reject or fail
to reject the null hypothesis at the 0.005 level of
significance.
Step 8 of 8: State the conclusion of the
hypothesis test at the 0.005 level of significance. (There is
sufficient evidence or there is not sufficient evidence)
Step 1
H0: political affiliation and age are independent
Ha: political affiliation and age are dependent
Step 2 and Step 3 Combined
Step 4
Test Statistics
The Chi-Squared statistic is computed as follows:
Step 5
The number of degrees of freedom is
Step 6
Based on the information provided, the significance level is α=0.005 , the number of degrees of freedom is df = 4, so then the critical value is 14.86 and the rejection region for this test is
Step 7
Since it is observed that , it is then concluded that the null hypothesis is not rejected.
Step 8
It is concluded that the null hypothesis Ho is not rejected. Therefore, there is NOT enough evidence to claim that the two variables are dependent, at the 0.005 significance level.
The corresponding p-value for the test is
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