1. Assume that the number of miles a particular brand of tire lasts before it needs to be replaced follows a normal distribution with a mean of 45,600 miles and a standard deviation of 5,800 miles. What is the probability that the next tire of this brand will last less than 42,000 miles before it needs to be replaced?
2. Suppose that the average grade point average (GPA) for the undergraduate student population at Goldey-Beacon College is 3.10. The following is a random sample of the GPAs of five students from the college. Calculate and interpret the sampling error. 2.45 3.76 3.48 2.81 3.34
3. According to the Organization for Economic Cooperation and Development (OECD), adults in the United States worked an average of 1,794 hours in 2007. Assume that the population standard deviation is 400 hours and that a random sample of 50 U.S. adults was selected.
a. Calculate and interpret the standard error of the mean.