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Q48. What are some of the common ways by which Fishbone Diagram is misused? Fishbone diagram is also called as ishikawa diagram or Cause & Effect diagram. It is a visual tool used to segment the possible causes that is impacting the final product or service. It is helpful for identifying the root cause that is creating the problem. Brainstormed ideas are collected and structured in the way using fishbone diagram. This helps categorizing the ideas gathered immediately into fishbone to identify the root cause. Types of Fishbone – Ø Process fishbone Ø Time –delay fishbone Ø Cause & Effect diagram with additional cards Ø Desired result fishbone Ø Reverse fishbone diagram History Professor Ishikawa created this cause and effect diagram in 1960’s.. This diagram based approach is used to think through all the possible causes that is creating the problem. This helps to carry a thorough detailed analysis of the problem. Steps to be followed: There are four ways how you have to use this diagram. They are as follows. 1. Identify the problem 2. Brainstorm the factors or all X’s involved. 3. Categorize and identify possible causes 4. Analyze the diagram Step Description Tools used Identify the problem identify the problem and write it at the head. Also gather data relating to who has done it, why it is done, where it is happening, what is the impact, what process is involved 3W1H technique is used to narrate the problem statement effectively. Work out factors involved Brainstorm and list all the factors or X's involved, irrespective of its criticality. If required, mark all these in white board for all members understanding and coordination. Brainstorming is used to list the factors Identify the possible causes Brainstorm each of the factors listed above separately and draw as each of the bones of the fish. If required, the causes can be broken further into sub causes. Brainstorming is used to list the possible causes Analyze the diagram After completing the entire diagram, depending on the criticality and complexity of the cause and problem, investigate further using why why analysis and so on. 5Why analysis, Prioritization matrix, Multivoting technique to priotize the possible causes. Fishbone framework: 1. 5M – Methods, Materials, Manpower, Measurement, Machines and environment 2. 5P – policies, procedures, people and plant, and place. (By service industry) 3. 7S – Strategy, Structure, systems, shared values, Skills, Style, Staff (used by McKinsey) 4. 4P – Product, place, price, promotion (used by Marketing) Example – A person having frequent sore throat think through and list all the possible causes in the fishbone diagram. Here it looks like. The possible cause of this issue is lifestyle. There can be many root causes to it. Modifying the lifestyle will help improve the condition of the person. Hence this is how it should have been done. Possible ways of Misusing the fish bone: 1. Limited thinking will not solve the purpose of using fishbone. Eg. If there is a time constraint during brainstorming session, the more information will not be collected due to other work related pressures. 2. Limited resources: If the person gathering is freeze with only 6 or 7 categories, then he may be in a position to categorize all the factors into these factors listed only. Resource can be in the form like paper and pen, time, whiteboard, employees involved in the process. Verbally conducted RCA session using fishbone will result in listing relevant and irrelevant possible causes into the diagram. 3. Inefficient people: If the fishbone is done using inefficient people, then there exists a failure. Fresher may not know the end to end process. In such case, if the fishbone is done using these fresher’s, the possible causes may not be a true event. It is vice versa. Hence a mix of tenurity should be involved in brainstorming and fishbone diagram. 4. Biased in collection of information: During brainstorming, all the team members should be involved and all the ideas should be noted down. If there is any subjective bias in noting down the points or self-judging the causes will not lead into an effective RCA using fishbone diagram. 5. Biasness in effective decision making: when the possible cause is irrespective of its relationship to the problem, the decision making becomes a waste. It may not yield you a best result. Inappropriate categorization of possible factors, and having the same point under multiple categorizes might lead into wrong decision making on the possible causes that affects the problem. Thanks Kavitha

Q 44. Can Type 1 Error of one situation be considered as Type 2 Error in a different situation? In other words, can Null Hypothesis statement for one situation be the same as Alternative hypothesis for another situation? Null Hypothesis: It is commonly denoted as Hsub0. This is typically a standard observation made by the researcher to say that there is no interaction between these variables. It is called null hypothesis. Alternate Hypothesis: It is denoted as Hsub1. Opposite of null hypothesis is alternative hypothesis, also called as researcher hypothesis, which is their prediction and measured for existence of relationship between these variables. Significance: Statistical tests are done to determine the relationship is significant. It also means that the difference in the results are not by random chance. Type 1 & Type II errors: No hypothesis is 100% certain for decision making. Because it is based on the probability value, there is chance of making a wrong decision as well. There are two types of errors possible in hypothesis. Type I and type II errors. Type I errors are when the null hypothesis is true and you reject the null. This is denoted by level of significance. Type II errors are when the null hypothesis is false and you fail to reject the null and accept alternative. This is denoted by Power test. Truth about the population Decision based on sample H0 is true H0 is false Fail to reject H0 Correct Decision (probability = 1 - α) Type II Error - fail to reject H0 when it is false (probability = β) Reject H0 Type I Error - rejecting H0 when it is true (probability = α) Correct Decision (probability = 1 - β) Negations: There are certain negations before making any hypothetical statements. Null hypothesis: “x is equal to y.” Alternative hypothesis “x is not equal to y.” Null hypothesis: “x is at least y.” Alternative hypothesis “x is less than y.” Null hypothesis: “x is at most y.” Alternative hypothesis “x is greater than y.” Example of Null and alternative hypothesis with 2 types of errors. · Null hypothesis (H0): μ1= μ2 The two medications are equally effective. · Alternative hypothesis (H1): μ1≠ μ2 The two medications are not equally effective. In the above example, the errors would be defined as Type I error – if the physician rejects the null hypothesis and concludes that the 2 medications are different when actually it is not. Type II error – If the physician fails to reject the null and concludes that the 2 medications are same when actually it is not same. Type II error is sometimes serious or life threatening. Having considered the consequences of the risk or seriousness of commiting one type of error, the decision is taken accordingly. Refernce: http://support.minitab.com/en-us/minitab-express/1/help-and-how-to/basic-statistics/inference/supporting-topics/basics/type-i-and-type-ii-error/ Another Example Null hypothesis - Earth is not at the center of universe. Alternative hypothesis - The Earth IS at the center of the Universe. In such statements, instead of proving one of the favorable conditions only, you have to first disprove that the theory of rejecting the null is equally important to accept the alternate. It is to just prove that the study or experiment conducted is flawless. If you only prove the alternate to be effective and not proving null to be rejected would set a system failure. Type I Error : In this example, the astronaut concludes by watching the sky over nights and conclude that the all other planets revolve around the earth. Hence the earth is at the centre of universe. So, alternate is proven. And the null is rejected. Type II Error – Here the astronaut concludes that the planet is not revolving around the earth. In fact the earth is revolving aroudnd the planets. Hence the earth is not at the center, because it keeps moving. Here he fails to reject the null and accept it, when actually it is not. Conclusion: So, to conclude the hypothesis statements depends on the situations we study and it is equally important to disprove the one with accepting the other hypothesis. Typically the null hypothesis says that there is nothing new happened either before and after or after the solution implemented. The difference is equal to 0. Generally, the people’s claims are always true until proven otherwise. If we have to prove, show evidences to reject the null hypothesis. To conclude the 2nd part, a null hypothesis can never be a alternate hypothesis in any type of situations, since the null hypothesis is generally a work done to nullify the statements or claims by people. Whereas the alternative hypothesis is a opposite nature of null hypothesis. It is not a equalized statements. It can be greater or lesser of the effect studied. Thanks Kavitha