Construct the appropriate control chart for the observations listed below, using 3 sigma limits.

Question

Product Number - Number of defects
1 - 3
2 - 3
3 - 6
4 - 5
5 - 3
6 - 5
7 - 2
8 - 2
9 - 3
10 - 4
11 - 6

a. Determine the upper and lower control limits.

b. Discuss the chart you have plotted. What conclusions and recommendations do you make from the chart and the data?

Answer 1

Here's what you will need to answer this question:

Lower limits = mean - 3(sd/√n)
Upper limits = mean + 3(sd/√n)

sd = standard deviation
n = sample size

You will need to calculate the mean and standard deviation from the data given. Once you have those values, you can then determine the lower and upper limits.

I hope this will help get you started.