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Lectures 4 & 5 Quality Managing Tools WHY DO WE USE QUALITY MANAGEMENT TOOLS? Helps to solve problems Helps identify reasons for problems Narrows down your observations Makes decision making easy Brings rationality to your claims Quality Managing Tools Basic Steps to Solve Problems: Define the problem and establish an improvement goal Collect data Analyze the problem Generate potential solutions Choose a solution Implement the solution Monitor the solution to see if it accomplishes the goal Quality Managing Tools There are 07 Basic Tools of Quality identified as being most helpful in troubleshooting quality issues. They are called basic because they are suitable for people with little formal training in statistics. These are : Flow Chart Cause & Effect Diagram Check Sheet Pareto Chart Histogram Scatter Plot Control Chart Flow Charts It visually represent relationships among the activities and tasks that make up a process. A Flowchart may: • Have a logical start and an end. • Have Inputs and outputs. • Indicate resources involved in the process. • Mention sequence of activities. • Show controlling points. • Mention activities responsible. Symbols in Flowcharting Following standard symbols are used to create process maps: Document/ Terminal Process Step Decision Report Input/ On-page Page Existing Output Connector Connector Process Manual Delay Manual Operation Input Types of Flow Charts Three (03) types of flow diagrams can be used to describe a process, depending upon the information to be shared. These are: High-Level Flowchart A first-level or top-down flowchart shows the major steps in a process. It illustrates a "birds-eye view" of a process. Types of Flow Charts Detailed Flowchart It maps all the steps and activities that occur in the process including decision points, waiting periods, documents and feedback loops etc. Types of Flow Charts Deployment or Matrix Flowchart It maps out the process in terms of who is doing what and how in a process. It is in the form of a matrix, showing the various participants and the flow of steps among these participants. Creating a Flow Chart Define the process steps by observing the process Sort the steps into the order of their occurrence in the process Place the steps in appropriate flow chart symbols Add the decision points & controlling points Create the chart Get it peer-reviewed Modify if required Get approval and implement for intended purpose Flow Charts Exercise: Draw a process map showing the sequence, flow and interaction of activities involved in the process of selection of a GD pilot for Pakistan Air Force with the below mentioned activities: • Advertisement in newspaper • Applications receiving & scrutiny • Welcoming applicants at recruitment center • Admission • Conducting preliminary test • Preliminary Test results announcement • Arrangements for ISSB tests • Conducting ISSB protocol • ISSB results declaration • Call for interview • Interview conduct • Selection formalities completion Cause & Effect Diagram • Also termed as Ishikawa, Fishbone and Cause & Effect Diagram. • It visually represents the causes of a problem or effect and help you determine the ultimate source of the problem — the root cause. • It is used at the beginning of root cause analysis and planning. CATEGORY CATEGORY CATEGORY 4 5 6 EFFECT CATEGORY CATEGORY CATEGORY 3 2 1 Cause & Effect Diagram Draw Spine Mark Categories Define Problem Highlight issues Exercise Draw a fishbone diagram for investigating the reasons for higher turnover of employees No perks Check Sheet It is a simple document that is used for collecting data in real-time and at the location where the data is generated. This document is typically a blank form that is designed for the quick, easy, and efficient recording of the desired information Problem Frequency Total Hard to drive IIII 4 to Office IIIII 6 location Low Salary IIIIIIIIIIIIII 13 Lesser Perks IIIIIIIIIII 9 Salaries IIIIIIIIIIIIIII 15 getting higher High market IIIII 6 demand Flexibility in III 3 management TOTAL: 56 Pareto Chart It is a simple bar graph that ranks problems in order of magnitude to determine the priorities for improvement activities. Often called the 80-20 rule, the Pareto’s Principle is a way of separating the “vital few from the trivial many”. How to construct a Pareto Chart 1. Select the parameter to be studied 2. Frequency of parameter to be arranged in descending order 3. Percentage of each contributor to be calculated (Individual & Cumulative frequency) 3, 4, 6, 6, 9 13, 15 No of %age of total Cumm. Total Issues Categories complaints (%age) (%age) (Nos.) Salaries Getting higher 15 27 27 Low Salary 13 23 50 Lesser Perks 9 16 66 High Market Demand 6 11 77 Office Location 6 11 88 Hard to drive to 4 7 95 Flexibility In Management 3 5 100 TOTAL 56 100 Pareto Chart Scatter Plot A scatter plot is a classic statistical diagram that lets you visualize the relationship between numeric variables. For instance, if you have a table of data on cities, you could use a scatter plot to see if there is a relationship between population and crime levels. • If the points cluster in a band running from lower left to upper right, there is a positive correlation (if x increases, y increases). • If the points cluster in a band from upper left to lower right, there is a negative correlation (if x increases, y decreases). Scatter Plot HIGH POSITIVE CORELATION LOW NEGATIVE CORELATION HIGH NEGATIVE CORELATION NO CORELATION Scatter Plot Draw a scatter plot for the below given data: Height Weight (inches) (lbs.) 67 155 72 220 77 240 74 195 69 175 Run Charts A run chart is a line graph of data plotted over time. By collecting and charting data over time, you can find trends or patterns in the process Run Charts Draw a run chart for a pizza oven whose temperature is measured after every hour to see whether the required temperature is maintained or otherwise Noted Temp. Time (Celsius) Temperature Monitoring 1200 Hrs 280 350 1300 Hrs 285 300 285 285 275 280 290 275 1400 Hrs 270 250 280 270 280 285 275 1500 Hrs 285 220 200 1600 Hrs 280 150 Temp 1700 Hrs 275 1800 Hrs 220 100 1900 Hrs 275 50 2000 Hrs 285 0 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2100 Hrs 280 2200 Hrs 275 2300 Hrs 290 Types of Data • There are different types of data which are required to be differentiated based upon the type of tool to be used: Attribute Data (whole numbers) Variable Data (measurements points) It is important to know what type of data you will collect so you can determine what type of control chart to construct. Different charts will give different information. Attribute Data • These types of data are often referred to as discrete data. There are two kinds of attributes data: Yes/No Data Counting Data • Mail delivery was on time or not? • Is the submitted invoice correct or not • Is process under control or otherwise? • Number of defects in product • Number or items shipped incorrectly • Number of accidents per month Continuous Data • These types of data are often referred to as variable data and the observation can be measured to any decimal place you want if your measurement system allows it. • Some examples of variables data are sales in dollars, amount of time to make a delivery, height, weight, and costs etc. Statistical Concepts Arithmetic Mean (X) the average of data Median the middle value when the figures are arranged according to size For example, for the data 10, 13, 15, 20, 27, 34, 37, the median is 20. In case of even number of data, the median is the average of central two values Mode the value which occurs most often in data For example, for a data series 12, 14, 18, 18, 22, 22, 22, 25, 30, 30, the mode is 22 Range The difference between maximum and minimum values in data Variance The square root of standard deviation, i.e., variance s = sqrt of s or s² = s Statistical Concepts Standard Deviation ( ) Square of variance; formula is: 2 xi - x s =√ n Wher; X = mean of values of distribution n = No. of values used to calculate standard deviation xi = value of x for each item in distribution Standard Deviation • Shows amount of variation or "dispersion" from the average (mean, or expected value). • A low standard deviation indicates that the data points tend to be very close to the mean, whereas: • High standard deviation indicates that the data points are spread out over a large range of values. Control Charts • Control charts present the results of a process over time • They are used to determine if the process is under control • Can be used to monitor: Cost and Schedule variances Errors in process Control Chart- a typical illustartion Out of Control Process Out of Control Process The Rule of Seven in Control Charts Out of Control Process – Rule of Seven Histogram • A histogram is a type of bar graph for showing frequency distribution, or how often individual data points occur across the range of the data from low to high. • It represents frequency distribution by means of rectangles whose widths represent class intervals and whose areas are proportional to the corresponding frequencies How to draw a histogram • SELECT the measures to be examined. For example, you need to study things like time, weight, dimensions and speed etc. • COLLECT the data (use a check sheet) • PREPARE the frequency table in a sequential form • DESIGN the histogram (class interval and class width finalization) • DRAW the histogram in a graphical display (using bar graph) • INTERPRET the data and draw your observations Example - Evaluating contract finalization time periods Contracts Processing Time Days Contracts Days Contracts Days Contracts Days Contracts Days Contracts 16 1 26 0 36 1 46 0 56 0 17 0 27 0 37 0 47 0 57 0 18 0 28 1 38 2 48 2 58 1 19 0 29 0 39 0 49 0 59 0 20 1 30 1 40 4 50 0 60 0 21 0 31 0 41 0 51 1 61 0 22 0 32 2 42 2 52 0 62 0 23 0 33 0 43 0 53 0 63 0 24 1 34 1 44 0 54 3 64 0 25 0 35 0 45 0 55 0 65 1 Range: 65-16 = 49 Class Interval: 5 Class Interval: 49/5 = 9.2 (10) Example - Evaluating contract finalization time periods Range: 65-16 = 49 Class Interval: 5 Class Width: 49/5 = 9.2 (10) Interpretation of Histogram Interpretation of Histogram Statistical Process Control (SPC) To achieve the best results, start by (1) drawing up a process map, so you understand the process flow. Next, (2) analyze the process flows for the primary causes of problems and develop your cause-effect diagram. Then, (3) collect data using check sheets and (4) plot your data using a Pareto chart and/or (5) a histogram. Next, (6) determine the relationship of various variables in your cause-effect chain using a scatter chart. Once you have solved your problem, (7) use a control chart to ensure that the process is staying within process control limits — demonstrate process control.

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posted: | 11/12/2012 |

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Project Quality Management Lecture, Audit, inspection, QA, QC, Assurance, Control, Quality control

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