Answer:
We are given that Among 180 homes in Hyde Park, 25 were found to have unsafe radon levels. Among 230 homes in La Grange, 50 were found to have unsafe radon levels.
Claim : the two towns have different rates of unsafe radon levels.
Let and
be the rates of unsafe radon levels of Hyde Park and LaGrange respectively .
Among 180 homes in Hyde Park, 25 were found to have unsafe radon levels
So,
Among 230 homes in La Grange, 50 were found to have unsafe radon levels.
So,
We will use Comparing Two Proportions
Formula of test statistic :
Substitute the values
test statistic :
test statistic : −2.053
Refer the z table for p value
p value = 0.0202
α= 0.05
Since p value < α
So, we reject the null hypothesis that the two towns have same rates of unsafe radon levels.
So, Claim is true.