While the process was operating in control, 30 samples of size n = 5 were taken from a process that fills boxes of cereal and checked for weight. The average of the sample means was 370.0 grams, and the average of the sample ranges was 10.2 grams.

a.

Calculate 3signma control limits for mean and range charts to monitor this process.

b.

Recently six additional samples of size 5 have been taken from the cereal box filling line; the individual weights in grams are recorded in the following table:

Sample No.						Sample Mean	Sample Range
1	361.2	364.7	378.5	367.7	371.4	?	?
2	372.3	375.8	367.7	374.6	366.1	?	?
3	364.2	373.6	365.4	363.0	370.3	?	?
4	363.2	379.1	371.8	372.4	376.5	?	?
5	369.8	373.5	369.5	374.6	376.1	?	?
6	364.2	371.5	372.3	368.7	373.8	?	?

Calculate the mean and range for each sample.

c.

Draw the mean and range charts for this process. Plot the results of the six samples on the chart.

d.

Does the process appear to be in control?