COB 300 Operations Test 2 (Pal) Questions
with Complete Solutions
Why are samples taken? Correct Answ_To determine whether assignable variations are
present in the output of a process
Central Limit Theorem Correct Answ_Sample means will be normally distributed no matter
whatever distributions the samples follow
Types of Data Correct Answ_-Variable: data that measures a particular product characteristic
(continuous) (length or width)
-Attribute: data that counts items (discrete) - number of defective items in a sample
Variable Charts Correct Answ_- R chart
- X-bar chart
Attribute Charts Correct Answ_-p-chart
-c-chart
,Fundamental concept in Control Charts Correct Answ_-95.44% of all sample means fall
within +- 2 standard deviations
-99.74% of all sample means fall within +- 3 standard deviations
Generic Control Charts Correct Answ_-Have a center line that is the overall average
-Have limits above and below the center line at +- 3 standard deviations (usually)
Process centering Correct Answ_- X bar chart
- X bar is a sample mean
- Size of each sample is n
Process Dispersion (consistency) Correct Answ_- R chart
- R is sample mean
X Bar Charts Correct Answ_-Center line is the grand mean (x double bar)
-Points are X bars
Range (R) Charts Correct Answ_-Center line is the grand mean (R bar)
,-Points are R
Run tests Correct Answ_-Even if a process appears to be in control, the data may not reflect
a random process
-Even if points are in the control limits the process must be random
C Charts Correct Answ_-Used to count defects in samples of constant size
-Center line is the grand mean (c bar)
-Number of samples is m
P Charts Correct Answ_-Used to track a proportion (fraction) defective
-Center line is the grand mean (p bar)
-Number of sample is m
-Size of each sample is n
Improving Process Capability Correct Answ_-Simplify
-Standardize
-Mistake-proof
, -Upgrade equipment
-Automate
Centered Process Correct Answ_-3 sigma: defects 2,700 parts per million
-6 sigma: defects 0.002 parts per million
Non-Centered Process Correct Answ_-3 sigma: defects 67,000 parts per million
-6 sigma: defects 3.4 parts per million
Moment-of-truth analysis Correct Answ_-experience enhancers
-standard expectations
-experience detractors
(order qualifier/order winner)
True or False: X-bar chart and R chart should be used together to find if a process is under
control. Correct Answ_True
with Complete Solutions
Why are samples taken? Correct Answ_To determine whether assignable variations are
present in the output of a process
Central Limit Theorem Correct Answ_Sample means will be normally distributed no matter
whatever distributions the samples follow
Types of Data Correct Answ_-Variable: data that measures a particular product characteristic
(continuous) (length or width)
-Attribute: data that counts items (discrete) - number of defective items in a sample
Variable Charts Correct Answ_- R chart
- X-bar chart
Attribute Charts Correct Answ_-p-chart
-c-chart
,Fundamental concept in Control Charts Correct Answ_-95.44% of all sample means fall
within +- 2 standard deviations
-99.74% of all sample means fall within +- 3 standard deviations
Generic Control Charts Correct Answ_-Have a center line that is the overall average
-Have limits above and below the center line at +- 3 standard deviations (usually)
Process centering Correct Answ_- X bar chart
- X bar is a sample mean
- Size of each sample is n
Process Dispersion (consistency) Correct Answ_- R chart
- R is sample mean
X Bar Charts Correct Answ_-Center line is the grand mean (x double bar)
-Points are X bars
Range (R) Charts Correct Answ_-Center line is the grand mean (R bar)
,-Points are R
Run tests Correct Answ_-Even if a process appears to be in control, the data may not reflect
a random process
-Even if points are in the control limits the process must be random
C Charts Correct Answ_-Used to count defects in samples of constant size
-Center line is the grand mean (c bar)
-Number of samples is m
P Charts Correct Answ_-Used to track a proportion (fraction) defective
-Center line is the grand mean (p bar)
-Number of sample is m
-Size of each sample is n
Improving Process Capability Correct Answ_-Simplify
-Standardize
-Mistake-proof
, -Upgrade equipment
-Automate
Centered Process Correct Answ_-3 sigma: defects 2,700 parts per million
-6 sigma: defects 0.002 parts per million
Non-Centered Process Correct Answ_-3 sigma: defects 67,000 parts per million
-6 sigma: defects 3.4 parts per million
Moment-of-truth analysis Correct Answ_-experience enhancers
-standard expectations
-experience detractors
(order qualifier/order winner)
True or False: X-bar chart and R chart should be used together to find if a process is under
control. Correct Answ_True
