Question

2.2 What is Six Sigma? What does it focus on and what methodology is used in Six Sigma? [10 Marks] 2.3 Describe the five sampling methods. [10 Marks] 2.4 What operational problems are caused by excessive variation? List and describe them. [15 Marks] 2.5 What are dashboards and balance score cards? How do they support Six Sigma projects? [15 Marks] 2.6 Explain Deming's red bead and funnel experiments? What lesson do they provide? [10 Marks] 2.7 Exercise: a) Briefly explain how to calculate the dpmo metric [3 Marks] b) An airline wishes to measure the effectiveness of its baggage handling system. Suppose that the average number of bags per customer is 1.6 and the airline recorded 3 lost bags for 8000 passengers in one month. Find epmo (error per million opportunities). [5 Marks)

Answer 1

2.2
Six sigma was introduced by engineer Bill Smith in 1980, Its sn tool or a technique which makes sure that 99.9999 percent quality has maintained while processing, that is improvement of quality in the stage of process through identifying and removing the causes of defects even it involves minimizing variability in manufacturing.

Six Sigma has 2 methodologies based on Deming's Plan–Do–Study–Act Cycle. That is DMAIC (defone, measure, analyse, improve and control) is used for improving an existing business processes and DMADV(define, measure, analyse, design and verify the design ) used for creating new product or process designs.

2.3
Simple random sampling - here sample is taken from the larger population N, the subset of population ( sample)is n.

Stratified sampling - here the population is divided into groups, based on some characteristic and groups are called strata

cluster sampling - here the population is divided into the separate groups, called clusters.

Multistage sampling - here we select the sample by using combinations of different sampling methods.

Systematic random sampling - here we create a list from the population then we randomly select the first sample element from the first k elements and sekection will continue till kth element on the list.

2.4
The disparity between an actual measure of a product characteristic and its target value is termed as variation where as excessive variation is somewhere the upper and lower acceptable limits which is established for a product specification,
Which may cause,
*decreased capacity utilization
*unreliability
*product discard
*salvage

2.5
The Balanced Scorecard moves from up to down, starting from objectives and then moves down to KPIs (key performance indicators)level,scorecard focuses on a given metric and compares it to a target,where as dashboard comes at operational level, involves presenting multiple numbers in different ways to support the strategy.

2.6
Red bead experiment says that its necessary to understand the system before making any changes for defect control or quality improvement. Its an illusion of bad management where too many employees and the rigid procedures do not allow workers to maintain quality when there is a defect in system.
The funnel experiment describes the adverse effects of too much adjusting a process when not required. When we adjust the process in response to random variation,then probably we are overadjusting the process and it leads to more variation in the process than would occur if a random cause process is left alone( without adjustment ).

2.7
A) DPMO = Total Number of Defects found in Sample / (Sample Size * Number of Defects Opportunities per Unit in the Sample) * 1000000
B) epmo = 3/(8000*1.6)*1000000
                 = 234.375