well-established research company conducts a random survey of 5241 people asking whether or not they like Coffee Brand X. The company determines that only 18% of respondents like Coffee Brand X. The research company publishes their findings in a peer-reviewed statistics journal.

Question

The company that makes Coffee Brand X conducts their own survey. The coffee company calls 20 people who recently purchased Coffee Brand X, asking whether or not they like Coffee Brand X. The company determines that 9 out of 10 people like Coffee Brand X, and they publish their findings on the company website.

Which of the following statements is true regarding these surveys?
A.
The coffee company's survey is likely to be biased based on the sample method and size.

B.
The research company's survey is likely to be flawed as so few people selected the coffee brand.

C.
There must have been a calculation error in one of the surveys for the survey results to be so different.

D.
The results of both surveys are valid even though different sample methods and sample sizes were used.

Answer 1

A. The coffee company's survey is likely to be biased based on the sample method and size.

This statement is true. The coffee company's survey has a very small sample size (20 people) and specifically targets individuals who have recently purchased Coffee Brand X. This group is likely to have a positive bias towards the brand, as they have already chosen to buy it, leading to an overrepresentation of positive responses. In contrast, the larger, random survey conducted by the research company provides a more comprehensive view of the general population's opinion on Coffee Brand X.