Use Table IX on page 13-74 to find the values of D3 and D4 for each of the following sample sizes.

a. n = 4

b. n = 12

c. n = 24 13.26 Construct and interpret an R-chart for the data in Exercise 13.10 (p. 13-29).

a. Calculate and plot the upper control limit and, if appropriate, the lower control limit. NW

b. Calculate and plot the A, B, and C zone boundaries on the R-chart.

c. Plot the sample ranges on the R-chart and use patternanalysis Rules 1–4 of Figure 13.22 to determine whether the process is under statistical control.