A new coin machine printing nickels is being tested by the Mint. Ten samples, with each using 10 nickles, are weighed. Each nickle should weigh 5 g and each sample should weigh 50g. The data collected is shown in the chart below:

Sample	Sample Mean (g)	Range (g)
1	49.998	0.017
2	50.001	0.011
3	50.025	0.025
4	50.121	0.005
5	50.012	0.001
6	49.953	0.004
7	49.999	0.007
8	50.002	0.022
9	50.007	0.001
10	49.099	0.014

A) Determine the upper and lower control limits and the overall mean for the x bar chart and the R chart (10 marks)

B) Draw the charts and plot the values of the sample means and range. (5 marks)

C) Should the mint invest in this new machine? Explain (5 marks)

Hint: Use the formulas related to the 3-sigma chart in the text and lesson notes.

The variables A2, D3, and D4 come from the chart. You can determine which row to use based on the value of “n” provided in the question.

See the example in the lessons for a good guideline.

You can draw the charts in Excel. If you are not sure how to do this there are good Youtube videos you can search on “how to draw statistical process control charts on excel”.