Greenstone Coffee is experiencing financial pressures due to increased competition for its numerous urban coffee shops. Total sales revenue has dropped by 15% and the company wishes to establish a sales monitoring process to identify shops that are underperforming. Historically, the daily mean sales for a shop have been $11,500 with a variance of 4,000,000. Their monitoring plan will take a random sample of 5 days' sales per month and use the sample mean sales to identify shops that are underperforming. Establish the lower limit sales such that only 5% of the shops would have a sample sales mean below this value.