A marketing student is estimating the average amount of money that students at a large university spent on sporting events last year. He asks a random sample of 75 students at one of the university basketball games how much they spent on sporting events last year. Using this data he computes a 99% confidence interval, which turns out to be ($117. $477). Are his conclusions valid or invalid? Why? a. Sampling Plan is flawed b. Sample Size is large enough