A TiW layer is deposited on a substrate using a sputtering tool. The following table presents data, in Angstroms, from 20 subgroups of n = 4. (a) Plot an x-bar and R control chart for this process. Performs runs tests to Western Electric rules 1 through 4 in Table 5.1, p. 197 of the textbook. Is the process in control? Revise the control limits as necessary. (b) Estimate the mean and standard deviation of the revised process. (c) Is the layer thickness of the revised process normally distributed? (d) If the specifications are 450 30 Angstroms, estimate the process capability. Subgroup X2 449 440 444 463 457 X1 459 443 457 469 443 444 445 446 444 432 445 456 459 441 460 453 451 422 456 449 455 452 463 452 457 445 465 453 X3 435 442 449 453 445 456 450 449 457 463 453 436 441 438 457 451 450 437 448 454 X4 450 442 444 438 454 457 445 452 440 443 438 457 447 450 438 435 444 457 460 431 446 450 429 467 444 450 454 A TiW layer is deposited on a substrate using a sputtering tool. The following table presents data, in Angstroms, from 20 subgroups of n = 4. (a) Plot an x-bar and R control chart for this process. Performs runs tests to Western Electric rules 1 through 4 in Table 5.1, p. 197 of the textbook. Is the process in control? Revise the control limits as necessary. (b) Estimate the mean and standard deviation of the revised process. (c) Is the layer thickness of the revised process normally distributed? (d) If the specifications are 450 30 Angstroms, estimate the process capability. Subgroup X2 449 440 444 463 457 X1 459 443 457 469 443 444 445 446 444 432 445 456 459 441 460 453 451 422 456 449 455 452 463 452 457 445 465 453 X3 435 442 449 453 445 456 450 449 457 463 453 436 441 438 457 451 450 437 448 454 X4 450 442 444 438 454 457 445 452 440 443 438 457 447 450 438 435 444 457 460 431 446 450 429 467 444 450 454