You are the manager of a local cinema, and want to investigate how much the average customer spends on the concession stand. You take a sample of 20 customers, and you find a sample average of $11.38, with a sample standard deviation of 3.33. Using this information, you want to create a 90% confidence interval around the population mean. What is the lower bound (lower end) of the confidence interval in of your analysis? Note: 1- Do not round intermediate numbers. Round your final answer to two decimal places