A simple random sample of 1000 American adults found that the average number of hours spent watching television during a typical week was 13.

A simple random sample of 1000 American adults found that the average number of hours spent watching television during a typical week was 13.8. A simple random sample of 500 Canadians yielded an average of 12.5 hours per week of television viewing. Assume that the American and Canadian distributions for weekly television, viewing times have the same standard deviations. The sampling variability associated with the sample means (described above) is