Eighty packages have been randomly selected from a frozen food warehouse, and the age (in weeks) of each package is identified. Given the frequency distribution shown, determine the approximate mean and standard deviation for the ages of the packages in the warehouse inventory.
Data for Exercise 3.41
Age (Weeks) Number of Packages
0–under 10.......... 25
10–under 20........ 17
20–under 30........ 15
30–under 40.......... 9
40–under 50........ 10
50–under 60.......... 4