Question

a hospital did a ten - year study on patients who used its services. one thousand patients were randomly selected and followed over a period of ten years to determine the average number of visits per year. by the end of the ten year period some of the patients had left the area. identify the problem with the poll. (1 point) the conclusion is based on a voluntary response sample. some of the sample data are missing. the relationship between two variables implies one causes the other. a nonresponse occurred.

Explanation:

Since some patients left the area by the end of the ten - year period, data on their visits for the entire ten - year span is unavailable. This means some of the sample data are missing. It's not a voluntary response sample as patients were randomly selected. There's no indication of a causal relationship assumption between variables, and non - response implies patients not answering surveys etc., which isn't the case here as they left the area causing data unavailability.

Answer:

Some of the sample data are missing.