In sludge county, a sample of 50 randomly selected citizens were tested for pinworm. of these, 11 tested positive. the cdc reports that the u. s. average pinworm infection rate is 12%. test the claim that sludge county has a pinworm infection rate that is greater than the national average. use a 0.05 significance level. (a) what is the sample proportion of sludge county residents with pinworm

(a) 0.22

Step-by-step explanation:

Given : In Sludge County, a sample of 50 randomly selected citizens were tested for pinworm. Of these, 11 tested positive.

Then, the sample proportion of Sludge County residents with pinworm will be :-

Hence, the sample proportion of Sludge County residents with pinworm = 0.22

Hypothesis for test :

, since alternative hypothesis is right tailed so the test is a right-tailed test.

Test statistic :

p-value : P(z>2.18)=0.0146287

Since p-value (0.0146287) is less than the significance level (0.05) , so we reject the null hypothesis.

Conclusion : Sludge County has a pinworm infection rate that is greater than the national average.