SME_8e_Ch_21_Section_3

# SME_8e_Ch_21_Section_3 - CHAPTER 21 SECTION 3: STATISTICAL...

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1 CHAPTER 21 SECTION 3: STATISTICAL PROCESS CONTROL MULTIPLE CHOICE 61. The mean of the sample means and the pooled standard deviation of 25 samples of size 4 taken from a production process under control are found to be 150 and 10, respectively. The centerline for the x chart is: a. 150 b. 100 c. 250 d. 6 ANS: A PTS: 1 REF: SECTION 21.3 62. To determine whether the process distribution standard deviation has changed, we use a(n): a. x chart. b. S chart. c. p chart. d. All of these choices are true. ANS: B PTS: 1 REF: SECTION 21.3 63. To determine whether the proportion of defectives is in line with specifications, we use a(n): a. x chart. b. S chart. c. p chart. d. All of these choices are true. ANS: C PTS: 1 REF: SECTION 21.3 64. Control charts used to determine if the process distribution standard deviation has changed are: a. x and p charts. b. p and R charts. c. R and S charts. d. S and x charts. ANS: C PTS: 1 REF: SECTION 21.3 65. The mean of the sample means and the pooled standard deviation of 40 samples of size 5 taken from a production process under control are found to be 400 and 15, respectively. The lower control limit for the x chart is: a. 460.37 b. 392.88 c. 379.88 d. None of these choices. ANS: C PTS: 1 REF: SECTION 21.3

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66. If the upper and lower specification limits of a process are 0.852 and 0.828, respectively, and the process standard deviation is 0.002, then the process capability index C p is a. 0.024 b. 2.000 c. - 2.000 d. 12.000 ANS: B PTS: 1 REF: SECTION 21.3 67. The mean of the sample means and the pooled standard deviation of 50 samples of size 10 taken from a production process under control are found to be 225 and 16, respectively. The upper control limit for the x chart is: a. 231.79 b. 240.18 c. 218.21 d. 209.82 ANS: B PTS: 1 REF: SECTION 21.3 TRUE/FALSE 68. When the purpose of sampling is to detect when a process becomes too variable, the control chart of choice will be an S chart. ANS: F PTS: 1 REF: SECTION 21.3 69. For an x chart, the lower and upper control limits are usually set at three standard errors from the centerline. ANS: T PTS: 1 REF: SECTION 21.3 70. A process capability index ( C p ) of 2.0 describes a production process where the specification limits are equal to 3 standard errors above and below the centerline. ANS: F PTS: 1 REF: SECTION 21.3 71. The process capability index measures the capability of the process to produce units whose dimensions fall with in the specifications. ANS: T PTS: 1 REF: SECTION 21.3 72. A coffee machine fills cups with an average of 6 ounces with a standard deviation of 0.25 ounces. A sample of 9 cups is taken. The lower and upper control limits for a 3-sigma x control chart are 5.75 and 6.25, respectively. ANS: T
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## This note was uploaded on 09/28/2010 for the course FINOPMGT 250 taught by Professor Kumar during the Spring '10 term at University of Massachusetts Boston.

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SME_8e_Ch_21_Section_3 - CHAPTER 21 SECTION 3: STATISTICAL...

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