You have just been promoted to district sales manager for the parts store chain and corporate wants you to estimate the promotion dollars that will be needed for your districts next quarter. You have assembled the following data from the past eight year's history for the projected quarter. You want to be 90% confident about your prediction. The sample standard deviation is $2900. 24,000 29.000 28,000 25.000 27,000 30.000 23.000 31,000 CC =