The manager of the local Walmart Supercenter is studying the number of items purchased by customers in the evening hours. Listed below is the number of items for a sample of 30 customers. 15 12 5 8 4 6 6 7 11 9 8 14 9 12 5 4 19 6 18 19 6 10 11 5 10 9 13 12 13 w Click here for the Excel Data File a. Find the mean and the median of the number of items. (Enter the "Median" to whole number and round your "Mean" to 1 decimal place.) Mean Median Check my work b. Find the range and the standard deviation of the number of items. (Enter the "Range" to whole number and round your "Standard deviation" to 3 decimal places.) Range Standard deviation c. Organize the number of items into a frequency distribution. (Enter the "Midpoint" and "Frequency" to whole number and round your class interval to 1 decimal place.) Class Midpoint Frequency 3.5 up to up to up to up to up to d. Find the mean and the standard deviation of the data organized into a frequency distribution. (Round "Mean" to the nearest whole number and "Standard deviations" to 3 decimal places.) Mean Standard deviation