Q3 - This is all the relevant information. It is a short question.

The time to replace vehicle wiper blades at a service center was monitored using a mean and a range chart. Six (6) samples of n = 20 observations were obtained and the sample means and ranges computed.

a. Using the factors in the table below, determine the upper and lower limits for me an and range charts.

b. Is the process in control?

Sample / Mean / Range

1 / 3.06 / 0.42

2 / 3.15 / 0.5

3 / 3.11 / 0.41

4 / 3.13 / 0.46

5 / 3.06 / 0.46

6 / 3.09 / 0.45