A study discusses a ovarian cancer ovarian

A study discusses a ovarian cancer ovarian cancer screening program that began in a certain country in 1996 and was expanded geographically through 2005. The people in the study were offered screenings every two years. The goal of the study was to compare? incidence-based rates of death from ovarian cancer across four groups. Data were analyzed for 62,786 people. Rates of death were reduced in the screening group as compared to the historical screening? group, and also in the non screening group as compared to the historical nonscreening group. Complete parts a through c below.

Is this an observational or experimental? study?

A.

The study is an experiment because at least one of the variables is controlled by the researchers.

B.

The study is an observational study because none of the variables are controlled by the researchers.

C.

The study is an observational study because at least one of the variables is controlled by the researchers.

D.

The study is an experiment because none of the variables are controlled by the researchers.

b. Identify the response variable and the explanatory variable.

The response variable is screening program

and the explanatory variable is death from ovarian cancer.? or vice versa?

c. Does the study prove that being offered screenings causes a reduction in death rates associated withovarian cancer

ovarian cancer??

A.

?Yes, the study found an association between the two variables.

B.

?Yes, there is anecdotal evidence connecting the two variables.

C.

?No, a lurking variable may exist that influences both variables.

D.

?No, it is unlikely that the two variables are connected.