Question

A researcher at a large university is studying the effects of multilingualism on  mental ability. He decides to study the faculty aged 35 to 55 at his university, looking separately at two groups: The ones that speak at least two languages  and the ones that don't.

There are over 400 faculty in each group, and he takes two independent, simple random samples of 45 individuals, one from each group for a detailed study. The study consists of a variety of tests.

Which of the following statements is most accurate?

Group of answer choices

This is a randomized-controlled experiment because the researcher randomly chooses the individuals from each group.

This is a controlled experiment because it has a treatment (multilingual) group and a control (monolingual) group.

This is an observational study because there is no control group --- all the individuals in the study take the same tests.

This is an observational study because the researcher doesn't choose who speaks more than one language and who doesn't.

In one part of the study, the researcher administers a pattern-recognition test to the sample faculty members, with the following results:

	Multilingual	Monolingual
Sample size	45	45
Average score	56	48
Sample SD	12	9

Using all the correct statistical calculations, the researcher finds that the observed difference between the sample averages  is “highly significant,”  (with a p-value less than 1%).

Which of the following statements is most accurate?

Group of answer choices

It is (very) likely that the difference in the sample averages is due to chance variation in the samples.

The difference in the sample averages is likely due to an actual difference between multilingual faculty and monolingual faculty.

The p-value is unreliable in this study because the sample size is too small.

The p-value has no useful interpretation in this study because it is observational.

Answer 1