The Organisation for Economic Co-operation and Development (OECD) surveyed 1000 people at random in each of its member countries in 2014 and found that the number of hours worked by Canadians was 1710 hours per year on average, whereas in the United States it was 1790. Assume that the standard deviation is 30% of these average values. In Canada, do people work fewer hours per year than people in the United States?

Answer this question:

a) Without pooling the estimates of the standard deviation.

b) With a pooled estimate of the standard deviation.

c) Why is it not possible to use the “paired samples” approach for this question?

d) At which significance level (0.01, 0.05, or 0.1) would your answers to (a) and (b) be different if the OECD had surveyed only 100 people in each country instead of 1000?