Question

Radioactive fallout from testing atomic bombs drifted across a region. There were 220 people in the region at the time and 42 of them eventually died of cancer. Cancer experts estimate that one would expect only about 28 cancer deaths in a group this size. Assume the sample is a typical group of people.

​a) Is the death rate observed in the group unusually​ high?

​b) Does this prove that exposure to radiation increases the risk of​ cancer?

Are the assumptions and the conditions to perform a​ one-proportion z-test​ met?

- Yes

- No

State the null and alternative hypotheses. Choose the correct answer below.

A.

H0​: pequals=0.12730.1273

HA​: pless than<0.12730.1273

B.

H0​: pequals=0.12730.1273

HA​: p not equals 0.1273p≠0.1273

C.

H0​: pequals=0.12730.1273

HA​: pgreater than>0.12730.1273

D.The assumptions and conditions are not​ met, so the test cannot proceed.

Determine the​ z-test statistic. Select the correct choice below​ and, if​ necessary, fill in the answer box to complete your choice.

A. z equals =

​(Round to two decimal places as​ needed.)

B. The assumptions and conditions are not​ met, so the test cannot proceed.

Find the​ P-value. Select the correct choice below​ and, if​ necessary, fill in the answer box to complete your choice.

A.

​P-value equals =

​(Round to four decimal places as​ needed.)

B.

The assumptions and conditions are not​ met, so the test cannot proceed.

Is the observed death rate unusually​ high? Choose the correct answer below.

A. The​ P-value is high enough to conclude that the death rate is unusually high.

B. The​ P-value is low enough to conclude that the death rate is unusually high.

C. The​ P-value is too high to conclude that the death rate is unusually high.

D. The assumptions and conditions are not​ met, so the test cannot proceed.

​b) Does this prove that exposure to radiation increases the risk of​ cancer? Choose the correct answer below.

A. Whether the death rate by cancer is unusually high or​ not, the cause cannot be determined.

B. No, there is insufficient evidence to conclude that exposure to radiation increases the risk of cancer.

C. Yes, there is sufficient evidence to conclude that exposure to radiation increases the risk of cancer.

D. The assumptions and conditions are not​ met, so the test cannot proceed.

  

Answer 1