Consider each situation described below. Identify the population and the sample, explain what p and p̂ represent, and tell whether the methods of this chapter can be used to create a confidence interval.

a) A total of 240 potato plants in a field in Prince Edward Island are randomly checked, and only seven show signs of blight. How severe is the blight problem for the Canadian potato industry?

b) Concerned about workers’ compensation costs, a small company decided to investigate on-the-job injuries. The company reported that 12 of its 309 employees suffered an injury on the job last year. What can the company expect in future years?