Grandfoods.xls Excel File
Grandfoods, Inc., makes energy
supplement bars for use by athletes and others who need an energy boost. One of
the critical quality characteristics is the weight of the bars. Too much weight
implies that too many liquids have been added to the mix and the bar will be
too chewy. If the bars are light, the implication is that the bars are too dry.
To monitor the weights, the production manager wishes to use process control
charts. Data for 30 subgroups of size 4 bars are contained in the Excel file Grandfoods under the Tab called “Main
Data”. Note that a subgroup is selected every 15 minutes as bars come off the
a. Use these data to construct the
appropriate process control chart(s). Make sure
you clearly label the important information on each chart.
what each chart is used for. Why do we need both charts?
c. Examine the control charts and indicate
which, if any, of the out-of-control signals are present. Is the process
currently in control?
d. Referring to the process control charts developed in part a., data for
periods 31 to 40 are contained in the file Grandfoods
under the Tab called “New Data”. Based on these data, what would you conclude
about the energy bar process?