A sample of the sales at 50 Haute Dog restaurants is taken and the sample mean is $30,000 per day with a sample standard deviation of $2000. The population standard deviation is not known. a. What is the 90% confidence interval for the daily sales at all restaurants? b. What is the probability that the average sales are really $32,000 or more per day? Assume that the population average is $30,000 per day and the std. Deviation is $2k.