In: Math
Pro-choice/Pro-life and Region of the Country: The results of a 2013 Gallup poll about people's position on abortion (pro-life or pro-choice) by region of the country are summarized in the contingency table below.
Observed Frequencies: Oi's
East | Midwest | South | West | Totals | |
Pro−Choice | 200 | 96 | 181 | 197 | 674 |
Pro−Life | 178 | 86 | 239 | 223 | 726 |
Totals | 378 | 182 | 420 | 420 | 1400 |
The Test: Test whether or not there is a dependent
relationship between abortion stance and region. Conduct this test
at the 0.05 significance level.
(a) What is the test statistic? Round your answer to 3 decimal places.
χ2
=
(b) What is the conclusion regarding the null hypothesis?
reject H0fail to reject H0
(c) Choose the appropriate concluding statement.
We have proven abortion stance and region are independent. The evidence suggests that there is a dependent relationship between abortion stance and region. There is not enough evidence to conclude that there is a dependent relationship between abortion stance and region.
ho: there is a independent relationship between abortion stance and region
h1: there is a dependent relationship between abortion stance and region
a)
Observed Frequencies | |||||
Column variable | |||||
Row variable | east | mid west | south | west | Total |
pro choice | 200 | 96 | 181 | 197 | 674 |
pro life | 178 | 86 | 239 | 223 | 726 |
Total | 378 | 182 | 420 | 420 | 1400 |
Expected Frequencies | |||||
Column variable | |||||
Row variable | east | mid west | south | west | Total |
pro choice | 181.98 | 87.62 | 202.2 | 202.2 | 674 |
pro life | 196.02 | 94.38 | 217.8 | 217.8 | 726 |
Total | 378 | 182 | 420 | 420 | 1400 |
(fo-fe)^2/fe | |||
1.784374 | 0.801465 | 2.22275 | 0.133729 |
1.656568 | 0.74406 | 2.063545 | 0.124151 |
chisq = sum(Oi-Ei)^2/Ei = 9.531
b)
df = (r-1)*(c-1)= (2-1)*(4-1) = 3
critical value, chisq(0.05, df) = 7.814
With chisq(3) > chisq(0.05, df), I reject the null hypothesis
c)
since ho is rejected, the conclusion is that there is a dependent relationship between abortion stance and region.
The evidence suggests that there is a dependent relationship between abortion stance and region.