The Watson Electric Company produces incandescent light bulbs. The following data on the number of lumens for 40-watt light bulbs were collected when the process was in control. (please show all work in detail)

OBSERVATION

Sample 1 2 3 4

1 504 512 488 500

2 497 501 507 503

3 481 470 485 492

4 520 505 495 488

5 490 514 508 504

Calculate an X-chart and R-chart based on the above data. Plot the X and R charts and state if the process is in control.