Question

2. A researcher is interested in testing the relationship between the amount of fat in one's diet and the development of cancer (of any type).

a. What is the research hypothesis? What is the null hypothesis?

b. How will the researcher determine whether or not there is a relationship between dietary fat and cancer? What steps will the researcher take?

c. Assume that the researcher made an error of the second type (i.e., a type II error). What did the researcher do to make this error?

Answer 1

Research's interest is to test the relationship between the amount of fat in one's diet and the development of cancer

a) Null Hypothesis Ho: There is NO relationship between the amount of fat in one's diet and the development of cancer

Alternative Hypothesis H₁ : There is relationship between the amount of fat in one's diet and the development of cancer

b) Researcher may go for an case control study.In case control study the outcomes captured first then exposure. Research may records few individual with cancer(cases) and few with non cancer (control). And then find out whether those cases were in fat diet( exposed) or not( non exposed) and similarly find out whether those controls were in fat diet( exposed) or not( non exposed).Then based on these data a chi-square test can be used to find if there is any association fat intake and cancer occurrence. If P-value is less than 0.01 then we can reject Ho at 1% alpha level that is there is a relationship.

c) Type 2 error means we failed to reject Ho when actually it is false.That is when there is a relationship present our test says there is no significant relationship.This type 2 error could be minimize by taking a large sample size.