Cost of Two-Year Colleges The dataset SampColleges4yr contains information for a sample of 50 US four-year colleges, selected from the population data in CollegeScores4yr. The Cost variable gives the average total cost for tuition, room, board, etc. at each school.

1. Use the Cost data in SampColleges4yr to find (and interpret) a 90% confidence interval for the average total cost at four-year colleges in the US.
2. Use the Cost data in CollegeScores4yr to find the mean cost for the population of all four-year colleges in the US. Does your 90% confidence interval from part (a) contain this mean cost?