A chocolate company makes candy bars to be used by elementary schools for fund-raising. One of the important quality characteristics is the weight of the bar. To monitor the weights, the production team wants to use process control charts. Data for 30 samples of four bars each are as follows:

Use Excel to develop an x Ì… chart to determine if the process is stable or not.

Sample Candy Candy Candy Candy Bar 2 7 2 7 7.60 7 6.82 7 8.64 7 7 7.25 8.69 7.64 7.28 7.99 12 7.25 15 7.58 7.58 7.32 16 7.63 8.11 7.42 7.42 17 8.04 7.48 6.88 7.62 6.59 8.98 8.16 7.16 19 6.42 6.86 7.04 6.35 20 7.88 7.20 8.10 7.12 2 725 7.38 7.31 7.81 6.89 7.34 6.64 7.81 23 8.04 7.22 8.04 6.48 24 7.63 7.20 6.94 6.85 25 7.44 7.98 7.18 7.61 26 6.92 9.29 8.11 6.83 27 8.22 7.31 7.28 8.72 28 7.82 6.78 8.59 7.92