To determine the performance of a chain of car dealerships, you are asked to analyze mean weekly sales by salesman. A representative sample of data was collected from one dealership in each region of the country and the results are presented in the table below showing weekly sales and frequency from this this sample. You are asked to create a confidence interval, with a width of 0.5, representing the mean number of weekly sales per salesman for all dealerships in the country, along with its level of confidence. [For example, the mean sales per salesman in for all dealerships is between _____ and ______ with a confidence level of _______%. All answers rounded to four decimal places.]