4. The Apparel Company makes expensive polo-style men's andwomen's short-sleeve knit shirts at its plant in Jamaica. Theproduction process requires that material be cut into largepatterned squares by operators, which are then sewn together atanother stage of the process. If the squares are not of a correctlength, the final shirt will be either too large or too small. Inorder to monitor the cutting process, management takes a sample of4 squares of cloth every other hour and measures the length. Thelength of a cloth square should be 36 inches, and historically, thecompany has found the length to vary across an acceptable averageof 2 inches.
Construct an R-chart for the cutting process using 3 sigmalimits.
RAC has taken 10 additional samples with the followingresults:
Samples | | Measurements (in.) | | |
1 | 37.3 | 36.2 | 38.2 | 36.3 |
2 | 33.4 | 35.4 | 37.3 | 36.2 |
3 | 32.1 | 34.8 | 38.1 | 35.7 |
4 | 36.1 | 36.5 | 36.2 | 34.2 |
5 | 35.1 | 37.3 | 35.2 | 33.1 |
6 | 33.1 | 35.3 | 35.3 | 32.3 |
7 | 38.4 | 39.1 | 35.1 | 32.2 |
8 | 35.1 | 36.8 | 36.1 | 34.5 |
9 | 37.4 | 39.5 | 37.2 | 36.2 |
10 | 32.1 | 34.4 | 35.5 | 36.3 |
Plot the new sample data on the control chart constructed aboveand comment on the process variability. What might you have learnedfrom this graph?
Construct an x-chart and an R-chart. Plot the sampleobservations provided above.
Use both of the x- and R-charts to comment on the process.
