Problem 2: We want to control a process for cutting plastic tubes, with a nominal length of 85 cm. Ten samples of 6 tubes each are taken (see table).

a) Draw the relevant control cards: calculate the control limits for this process, place the points accordingly on the cards and determine whether the process is under control.

b) You are informed that the specifications for plastic tubes in part a) above are : 84.5 cm - 87 cm. Based on the information available, estimate the percentage of plastic tubing that will meet the advertised limits.

Prlvement X1 X2 X3 X4 Xs X6 1 84 2 85.2 83,4 86.3 86.8 84.2 83.3 84.3 85,7 86,8 84.1 84,4 86.2 83.5 84.2 84,7 83.2 3 84,1 86,5 84,4 83,3 84.5 4 84.8 83.1 86,8 83,6 5 86,7 86.8 86 83.4 6 85.4 86.8 85,5 85,1 84.5 7 85.1 86 83,3 84.6 85,3 86,3 85,7 85.4 84,3 85 86,5 85.8 84.2 84.8 84.8 86.3 86,9 85,5 9 84,8 83,7 84.9 86,6 84.9 10 83.9 84.2