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1 Role of Statistical Techniques Prof. Dr. Masood Sadiq Butt

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Statistical tools to ensure the and get best quality of the product.


  • 1Role of Statistical Techniques

    Prof. Dr. Masood Sadiq Butt

  • 2Role of Statistical Techniques

    During processing of products, there are variations in product parameter

    Change in variables affect the quality of the product

    Variations can be due to trouble shooting, variables that normally goes off are temp,

    pressure and rate of fluid flow

    These variations are ascertained using statistical analysis to meet the standard

  • 3 Statistical techniques can help to measure,describe, analyze, interpret and model suchvariations

    Statistical techniques help to get rid of suchvariation even with small data

    Analysis of data help solve the variation inproduct parameters

    Preventive action, if applied aptly, will lead tocontinual improvement in the finished product

    For statistical analysis, sampling is of paramountimportance

  • 4Why 100% sampling cant be done ?

    We cant go for 100% sampling of the food product as

    It is a time consuming exercise

    Destructive sampling at such a mass level is not desired at industrial scale

    Financial burden on the industry as well

  • 5 Quality management system is that part of theorganization management system that focuseson the achievement of the results in relation tothe quality objectives

    Quality management system is used to satisfythe needs, expectations and requirements of theinterested parties

    Quality objectives complement other objectivesof the organization such as those related togrowth, funding, profitability, environment andoccupational health and safety

  • 6 Quality management system facilitate planning,allocation of resources, definition of

    complementary objectives and overall evaluation

    of the effectiveness of organization

  • 7Statistical Quality Control Tools

    Seven statistical quality control tools include

    1. Data sheet

    2. Cause-and-effect diagram

    3. Scatter diagram

    4. Flowchart

    5. Pareto chart (contains bars and line graph)

    6. Histogram (graphical representation, showing a

    visual impression of the distribution of data)

    7. Control chart

  • 8Data Sheet

    Data from a table, form, query, view, or stored procedure displayed in a row-and-column format

    Datasheet is a document summarizing the performanceand other technical characteristics of





    Subsystem (e.g. a power supply)


  • 9Data Sheet

  • 10

    Data Sheet

    Depending on the specific purpose, a data sheet mayoffer an average value, a typical value, a typical range,engineering tolerances,or a nominal value

    A data sheet is usually used for technicalcommunication to describe technical characteristics ofan item or product

    It can be published by the manufacturer to help peoplechoose products or to help use the products

    By contrast, a technical specification is an explicit set ofrequirements to be satisfied by a material, product, orservice

  • 11

    Cause-and-effect diagram

    Kaoru Ishikawa, one of the founding fathers of modernmanagement, created the cause-and-effect diagram

    Causes are arranged according to their level ofimportance or detail, resulting in a depiction ofrelationships and hierarchy of events

    This helps to identify areas where there may beproblems, and allows for comparison of their relativeimportance

    Cause-and-effect diagrams are typically constructedthrough brainstorming techniques

  • 12

    Cause-and-effect diagram

    Causes in a cause-and-effect diagram are frequentlyarranged into the four most common major categories

    Manpower, methods, materials, and machinery (formanufacturing)

    Equipment, policies, procedures, and people (foradministration and planning)

    Its also called as fish bone diagram

  • 13

    Cause-and-effect diagram/ fish bone diagram

  • 14

    Scatter diagram

    A scatter diagram or scatter chart is similar to a linegraph, except that the data points are plotted without a

    connecting line drawn between them

    Scatter charts are suitable for showing how data pointscompare to each other

    At least two measured objects are needed for the query(one for the x-axis and one for the y-axis)

  • 15

    Scatter diagram

    Scatter diagrams are used to study possiblerelationships between two variables

    Although these diagrams cannot prove that one variablecauses the other, they do indicate the existence of arelationship, as well as the strength of that relationship

    In a scatter diagram the horizontal axis contains themeasured values of one variable and the vertical axisrepresents the measurements of the other variable

  • 16

    Scatter diagram

    The purpose of the scatter diagram is to display whathappens to one variable when the other variable is


    The diagram is used to test the theory that the twovariables are related

    The slope of the diagram indicates the type ofrelationship that exists

  • 17

  • 18

    Flow Chart

    A flowchart is defined as a graphic representationemploying standard graphic icons, usually a series ofblocks with each block representing one major process,that describes an operation that is studied or is used toplan stages of a project

    Flowcharts provide an excellent form of documentationfor a process operation

    These are useful when examining how various steps inan operation work together

  • 19

    Flow Chart

    A flowchart is an important project development anddocumentation tool

    It visually records the steps, decisions, and actions ofany manufacturing or service operation and defines the

    system key points, activities, and role performances

    In a flowchart, the description of each process is writteninside the blocks

    Any other significant information is usually writtenoutside the blocks

    Each block is connected with an arrow to show wherethat process leads

  • 20

    Flow Chart

    The graphic icons generally used are:

  • 21

    Flow Chart

  • 22

    Pareto Chart

    Alfredo Pareto was an Italian sociologist who suggestedthat 80% of all wealth in this country is owned by 20% ofthe people.

    This supposition, known as the Pareto Principle wasfurther developed by business and industry leaders whofound that most of the quality problems were confined toa small number of machines or workers

    In other words, 80% of problems come from 20% of theequipment or workforce.

  • 23

    The Pareto Principle is used by business and industry to work to continually improve quality, whether it is a

    product or a service

    Quality improvement involves tackling one issue at a time

    By addressing the ones causing the most difficulty (the 20% that are causing 80% of the problem),

    improvements can be made and monitored for

    continuous progress

    Pareto charts are used to decide what steps need to be taken for quality improvement

  • 24

    Pareto Chart

    A Pareto chart graphically summarizes and displays therelative importance of the differences between groups ofdata

    A Pareto chart can be constructed by segmenting therange of the data into groups (also called segments,bins, or categories)

    The number of data points in each group is determinedand the Pareto chart constructed; however, unlike thebar chart, the Pareto chart is ordered in descendingfrequency magnitude

    The groups are defined by the user

  • 25

    Pareto Chart

  • 26


    A histogram is used to graphically summarize and display the distribution of a process data set

    It can be constructed by segmenting the range of the data into equal-sized bins (segments, groups, or classes)

    The vertical axis of the histogram is the frequency (the number of counts for each bin), and the horizontal axis is labeled with the range of the response variable

    The number of data points in each bin is determined and the histogram constructed

    The user defines the bin size

  • 27


  • 28

    Control Chart

    Control charting is one of the most technicallysophisticated tools of statistical quality control

    Dr. Walter A. Shewhart developed it in the 1920s as astatistical approach to the study of manufacturing

    process variation for the purpose of improving the

    economic effectiveness of the process

    These methods are based on continuous monitoring ofprocess variation

    A control chart is a graphical display of a qualitycharacteristic that has been measured or computed from

    a sample vs. the sample number or time

  • 29

    Control Chart

    The chart contains a center line that represents theaverage value of the quality characteristic corresponding

    to the in-control state

    Two other horizontal lines called the upper control limit(UCL) and the lower control limit (LCL) are also drawn

    These control limits are chosen so that if the process isin control, nearly all of the sample points will fall between


    As long as the points plot within the control limits, theprocess is assumed to be in control and no action is


  • 30

    Control charts are universally used to present qualitydata

    They are sufficiently simple to interpret so thatmisunderstandings are avoided

    Regardless of type, control charts all contain a fewfundamental characteristics:

    They contain upper and lower control limits within which allobservations will lie if the process is under control

    They contain a center line which is usually considered thetarget value for the process

    They generally show numbers along the vertical axis todefine the values of the control limits and observations

  • 31

    Control Chart

    Control charts are used as a proven technique for

    improving productivity tool in defect prevention prevent unnecessary process adjustments provide diagnostic information provide information about process capability

    A typical example of a control chart in the food industry isthat used for net weight control

  • 32

    Control Chart

  • 33

    Relationship b/w QMS and Excellence Models

    Approaches of QMS are based on certain principles that help to

    1. Enable an organization to identify strengths and weaknesses

    2. Contain provision for evaluation against generic models

    3. Provide a basis for continual improvement

    4. Contain provision for external recognition

  • 34

    Relationship b/w QMS and Excellence Models

    ISO 9000 family of standards providerequirements for QMS and guidance forperformance, improvement, evaluation

    Excellence models contain criteria that enablecomparative evaluation of organizationalperformance and is applicable to all activitiesand interested parties of an organization

    Assessment criteria in excellence modelsprovide a basis for an organization to compareits performance with the performance of otherorganizations