According to a survey from Statistics Canada (Table 2020107, “Earnings of Individuals, by Selected Characteristics and North American Industry Classification System (NAICS), 2011 Constant Dollars”), in 2011, the average earnings in Vancouver were $42,800 in Educational Services and $78,600 in the Financial Services industry.

a) Suppose the standard deviation of earnings in Educational Services for the whole of Vancouver was $12,500, and we want the standard deviation of average earnings in our survey to be $1000. What sample size do we need to take?

b) Suppose we used a sample of size 360 for our estimate of average earnings in Financial Services, and the standard deviation of earnings in our survey was $15,200. What is the standard error of the average earnings in Financial Services?