QUIZ2 DJF61082 QC

List the examples of assignable causes. CLO 1 C1

i.  New supplier

ii.  Temperature variation

iii. New untrained operator

iv. Raw material variation

• i and ii

• ii and iii

• i and iii

• iii and iv

The cause of variation can be eliminated. State the correct answer. CLO 1 C1

• Assignable cause

• Chance cause

• Variable cause

• Internal cause

Based on the above control chart, identify the cause of variation. CLO 1 C1

• Chance cause

• Assignable cause

• External cause

• Variable cause

A process produces 4000 parts per day and 75 parts are taken as a sample. Calculate the number of subgroups can be formed if size of sample is 5.

CLO 1 C3

• 10

• 12

• 15

• 18

The number of subgroups is 20 with a subgroup size of 5, choose the correct factors for control limit of  R-chart, D₃ and D₄ from Table B: factors for computing central lines and 3σ control limit.  CLO 1 C2      

• D₃ =0

  D₄ =0.282

• D₃ =0.076

  D₄ =1.924

• D₃ =0

  D₄ =2.574

• D₃ =0

  D₄ =2.114

If the sum of Xbar = 600,  the sum of range, R= 150, the number of subgroups is 20 with a subgroup size of 7. Calculate the upper control limit and lower control limit for  Xbar -chart.

CLO1 C3

• UCL =30.3

  LCL = 25.1

• UCL = 33.1

  LCL = 26.9

• UCL = 35.4

  LCL = 27.2

• UCL = 37.5

  LCL = 28.7

Based on the above control chart, choose the correct answer for the process. CLO 1 C2

• Process is capable

• Process is stable

• Process is out of control

• Process is in control

A company is attempting to determine whether an existing machine is capable of milling an engine part that has a key specification of 4 ± 0.003 cm. After a trial run on this machine, the company has found that the machine has mean of 4.001 cm with a standard deviation of 0.002 cm.

Calculate the Cpk for this machine. CLO 1 C3

• 0.67

• 0.52

• 0.46

• 0.33

The upper and lower specifications for a metal plate are 6.50 mm and 6.30 mm, respectively. The process mean is 6.45 mm, and the process capability index is 0.56. Calculate the process standard deviation. CLO 1 C3

• 0.01

• 0.03

• 0.05

• 0.08

A new process is started and the sum of the range for 20 subgroups of size 7 is 150. If the specification limits are 650±20, calculate the process capability index, Cp.

CLO1 C3

• 6.40

• 3.30

• 4.70

• 2.40