# Tutor profile: Kianoosh E.

## Questions

### Subject: Farsi

چه مفهومى را در بردارد؟ « اگر در ديدهٔ مجنون نشينى به غير از خوبى ليلى نبينى »: what does this ئثشد؟

You are not a true lover to understand the depth of and real meaning of what Majnoon sees from Leili. Only a true lover can really and truly realize it because the definition of beauty is completely different to his eyes.

### Subject: Manufacturing Engineering

What is six sigma and why do we need six of them?

the term derives from theories of Dr. Shwhart as well as the loss function developed by Taguchi, for eliminating defects (driving toward six standard deviations between the mean and the nearest specification limit) in any process – from manufacturing to transactional and from product to service. Back in old days, manufacturers were striving to produce "to spec" and have every part built within the specified tolerance; Taguchi showed variation within spec is costly. On normal distribution curve the predictable mean (expected value) is centered between the spec limits, and there is a statistical distance of three standard deviations (three sigma) from the average to the spec limits. Theoretically, 99.7% of all the products' property to be in the +/- spec (limits). Six sigma can be applied as a quality improvement method along with other methods a manufacturing facility to apply (DMAIC which is define, measure, analyze, improve and control) and assemble a set of quality tools to use in each phase of manufacturing. Six sigma project implementation often fails due to being poorly scoped. One would think that Six Sigma Black Belts - who usually receive four to six weeks' training in team facilitation, process management and improvement tools, and statistical analysis - would also be trained as project managers. This is not always true, however. Project management skills are usually left to chance in Six Sigma.

### Subject: Statistics

If we assume traveling times for an individual is normally distributed; with the mean value of 30 minutes, and standard deviation 16 minutes, find the probability that a travel duration is shorter than 36 minutes.

Using z-score [z = (x - mean)/st. dev and standard normal table: z = (36 - 30)/16 = 0.375, by using the table and rounding the number to .37, then the probability of commute time greater than this would be .3557; thus the probability of a commute shorter than this would be 1 - 0.3557 = 0.6443.

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