Chapter 26, Problem 30E

a)

To determine

To explain whether the survey is retrospective, prospective or an experiment.

Answer to Problem 30E

It is a Prospective study.

Explanation of Solution

Given:

  

Experimental study: Assigning people or things to groups and applying some treatment to one group, while the other group does not receive the treatment.

Observation study: In an observational study, measure or survey members of a sample without trying to affect them.

There are two types of Observational study:

Retrospective: The data are collected from the past by going back in time.

Prospective: The data are collected in the future.

This survey is prospective as data is collected in the future.

b)

To determine

To find which test is appropriate.

Answer to Problem 30E

Chi-square test of Independence.

Explanation of Solution

Given:

  

When we want to check whether the two variables are independent. Therefore, here research wants to check whether there is association between cancer and fish consumption. Hence, Chi-square test of Independence is appropriate.

c)

To determine

To explain whether there is evidence about association between cancer and fish consumption.

Answer to Problem 30E

There is not sufficient evidence to support the claim of an association between cancer and fish consumption.

Explanation of Solution

The null and alternative hypotheses:

H₀: There is no association between cancer and fish consumption.

H_a: There is association between cancer and fish consumption.

Using excel,

  

Therefore,

  ${\chi }^2$ = 3.68

P-value = 0.2985

Decision: The p-value> 0.05, fail to reject H0.

Conclusion: There is not sufficient evidence to support the claim of an association between cancer and fish consumption.

d)

To determine

To explain whether the study proves eating fish does not prevent prostate cancer.

Answer to Problem 30E

No.

Explanation of Solution

Given:

  

This survey is prospective as data is collected in the future. Therefore, there might be some lurking variables which affect on the results. So, there should be an experiment study to prove causation.