Question 1 


The following chart represents your sandwich prep time IMR control charts set of your sandwich process. You are the Lead Green Belt of a Quality Assurance Team that will report the findings to the management. Interpret the charts for Ms. Nguyen, your district manager.

Question 2


Use the following data decide if the outcome of an operation depends on the process used


ConditionProcess AProcess BProcess CProcess DProcess E
No improvement13582143
Partial improvement (less than goal)1810365629
Met improvement goal1616355110



































Question 3 (


Gabriel is working on a project to address the root cause of defective sub-assemblies.  It has been brought to Gabriel’s attention that a higher percentage of defectives are produced in the third shift. Gabriel collected the following data to check the validity of the above claim:

Test at 5% significance level to determine if the proportion of defectives is the same for all three shifts




TYPEFirst ShiftSecond ShiftThird Shift






























Question 4


The customer expectation when phoning a customer service line is that the average amount of time from completion of dialing until they hear the message indicating the time in queue is equal to 55.0 seconds (less than a minute was the response from customers surveyed, so the standard was established at 10% less than a minute).

You decide to randomly sample at 20 times from 11:30am until 9:30pm on 2 days to determine what the actual average is.  The actual data was as follows:

54.1, 53.3, 56.1, 55.7, 54.0, 54.1, 54.5, 57.1, 55.2, 53.8,54.1, 54.1, 56.1, 55.0, 55.9, 56.0 ,54.9, 54.3, 53.9, 55.0

What is a 95% confidence interval for the true mean call completion time?

What is the 95% confidence interval on the standard deviation



































Question 5

The following data represent the value of a certain quality characteristic of interest during a  LSS improvement project. Using your knowledge in SPC as Green Belt, please interpret the data and statistically state your case for Ms. Nguyen your district Manager



DateStageProject Metric
137/6/2015During Project81
147/13/2015During Project85
157/20/2015During Project83
167/27/2015During Project88
178/3/2015During Project86
188/10/2015During Project89
198/17/2015During Project87
208/24/2015During Project85
218/31/2015During Project90
229/7/2015During Project89
239/14/2015During Project92
249/21/2015During Project90
259/28/2015During Project93
2610/5/2015During Project89
2710/12/2015Post Project94
2810/19/2015Post Project97
2910/26/2015Post Project96
3011/2/2015Post Project91
3111/9/2015Post Project97
3211/16/2015Post Project98
3311/23/2015Post Project99
3411/30/2015Post Project94
3512/7/2015Post Project95
3612/14/2015Post Project97
3712/21/2015Post Project97
3812/28/2015Post Project96
391/4/2016Post Project97









Question 6


The operational data at a pizza processing facility in upstate New York are as follows:


One workday = 8 hours

Lunch time =30 min

Break (twice per shift) = 15 min each

Number of shifts = 2

Days per week = 5

Demand = 300 units per week

Total waiting time per unit = 75 min per unit

Delay from other activities = 30 min per unit

Compute the following:

  1. Takt time
  2. Pitch time
  3. Cycle Time
  4. Lead Time













Last Updated on February 11, 2019

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