MAHARASHTRA INSTITUTE OF TECHNOLOGY,AURANGABAD

(PLASTICS AND POLYMER ENGINEERING DEPT.)

PRESENTATION ON:-

STRATIFICATION : A PROBLEM SOLVING TECHNIQUE

NAME-ANSHUL GAUTAMPURKARCLASS- T.Y.ROLL NO.-T3715

What is a “Problem “?“Problem is an undesirable event” or ..

Any Gap between what is expected and what is obtained , can be called as a

Problem, and any effort to reduce this gap can be called as “Problem Solving”

Expected

Obtained

(Gap ?) A Problem!

A problem can be solved by two techniques:-Old Tools

Tally Sheet/Check Sheet

Pareto Diagram

Cause and Effect Diagram

Graphs/Histograms

Stratification

Scatter Diagram

Control Chart

1. By material Manufacturer, buyer, brand, place of production, purchasedate, lot received, production lot, components, purity, size, parts, time stored, storage place, etc.

2. By machine, equipment, or tool

Machine type , number, model, performance, and age: by factory, line, tool, and die.

4. By operating procedure and by operating conditions

Temperature, pressure, speed, rational frequency, linespeed,location of operation, illumination, air temperature,humidity,weather, operating procedure, etc.

3. By operator Individual, team, group, age, experiences, gender, etc.

5. By measurement and inspection

Instrument, measurement procedure, place of measurement.Person making the measurement, inspection tools, inspection procedures, place of inspection, inspector, etc.

6. By time Time, morning, afternoon, night, day, week, month, period season, etc: just before starting and just after finishing the operation.

7. By environment and weather

Air temperature, humidity, clear, cloudy, rainy, windy, snowy, rainy season, dry season, sound, illumination, etc.

8. Others New vs.. previous product, unit product vs.. continuouslyproduced product, good product vs.. defective product,packing method and transportation method etc.

Stratification

Definition

• Stratification is a technique used in combination with other data analysis tools. When data from a variety of sources or categories have been lumped together, the meaning of the data can be impossible to see. This technique separates the data so that patterns can be seen.

• Classification of a mass of data (obtained from research or survey) into categories and sub-categories on the basis of one or more chosen criteria.

• Hierarchical arrangement of a society into different layers (strata) on the basis of a distinguishing characteristic such as age, gender, life style, race, status.

Stratification

When to use ?

• Before collecting data.• When data comes from several sources or conditions, such as shifts,

days of the week, suppliers or population groups.• When data analysis may require separating different sources or

conditions.

Stratification

Purpose

The reason to stratify the data is to make it easier to find patterns. If there is a small problem on one day of the week and all the data is mixed together it may well not be noticable. By stratifying the data the data of interest can be made more visisble (of course that requires stratifying by the right characteristic)

Stratification

Procedure

• Before collecting data, consider which information about the sources of the data might have an effect on the results. Set up the data collection so that you collect that information as well.

• When plotting or graphing the collected data on a scatter diagram, control chart, histogram or other analysis tool, use different marks or colors to distinguish data from various sources. Data that are distinguished in this way are said to be “stratified.”

• Analyze the subsets of stratified data separately. For example, on a scatter diagram where data are stratified into data from source 1 and data from source 2, draw quadrants, count points and determine the critical value only for the data from source 1, then only for the data from source 2.

Stratification Considerations

• Here are examples of different sources that might require data to be stratified: – Equipment– Shifts– Departments– Materials– Suppliers– Days of the week– Time of a day– Products

• Survey data usually gets benefitted if stratification is used. • Always consider before collecting data whether stratification might be

needed during analysis. Plan to collect stratification information. After the data is collected it might be too late.

• On your graph or chart, include a legend that identifies the marks or colors used.

Category 1 Category 2 Category 3 Category 40

1

2

3

4

5

6

Diagrammatic representation of Stratification of a simple reactor:-

• Bar graph

Reactor 1

Reactor 2

Reactor 3

Stratification - Pareto Diagrams with Stratification

Pareto Diagram with Same-Size Categories

• Stratification and Cause-and-Effect Diagrams

– Stratification with Pareto Diagrams and Cause-and-Effect Diagrams

Stratification with Control Charts, Pareto Diagrams, and Cause-and-Effect Diagrams

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Method Usage Result

StratificationTo sum up

Grouping by day, time, place, worker, or process

X

Y

Z

Number of Units

★★★★★★★

△△△△

○○○

•Used to observe variations among strata.•Used to identify the relationship between cause and effect.•Used to identify a purpose and means to serve the purpose[Used during phases to monitor the situation, analyze causes, review effectiveness of an action, perform standardization, and implement a selected control measure.]

•Allows observation of variations among strata.•By performing a cause analysis using the stratified data, the following can be accomplished.

1.Identification and control of a problem 2.“Division of data (obtained by using each QC tool) into several groups”

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Thank you