MA145-B Fall2008 Assignment 4 - Five Number Summaries and Box Plots

A manufacturer of chocolate candies has the following quality control objectives at its production facility:

• The first quartile of the weight in grams should be between 11 and 13
• The third quartile of the weight in grams should be between 13 and 15
• There should be no outliers (i.e., all peices should fall between the upper and lower fences)

Each hour of a 12 hour shift, a sample of 120 pieces is taken from the production line and each piece is weighed.

Spreadsheet qc.xls contains the weights for the 12 samples taken on a particular day.

Instructions

• Using either MINITAB or a spreadsheet, compute the Five Number Summary for each of the 12 hourly samples.
• Using MINITAB, construct Box Plots of the 12 hourly samples on one chart.

Based on these results, does the company appear to be meeting its quality control objectives? If not, where has it failed to meet them?