The foreman in the welding department wanted to know what value of allowance to use for a particular section of the shop. A work sampling study was authorized. Only two activity categories were considered: (1) welding and other productive work, (2) personal time, rest breaks and delays. Over a four-week period, where there are 40 hours per week, 161 observations are made at random times. Each observation captured the category of activity of each of 12 welders in the shop section of interest. Results indicated that category 2 constituted 17 % of the total observations. (a) Can you conclude that realized PFD is 17 % in the factory at 100*(1-0.02) % confidence level with 7% precision? (b) If a total of 88 work units were produced during the 4 weeks, and all category 1 activity was devoted to producing these units, what was the average time spent on each unit?
Theory and Design for Mechanical Measurements
Measurement is a term that refers to analyzing a manufactured component regarding the degree of accuracy for dimensions, tolerances, geometric profile, roundness, flatness, smoothness, etc. Measurement always involves comparing the manufactured component or the prototype with a standard specimen whose dimensions and other parameters are assumed to be perfect and do not undergo changes with respect to time.Precisely in mechanical engineering the branch that deals with the application of scientific principles for measurements is known as metrology. The domain of metrology in general deals with various measurements like mechanical, chemical, thermodynamic, physical, and biological measurements. In mechanical engineering, the measurements are limited to mechanical specific such as length, mass, surface profile, flatness, roundness, viscosity, heat transfer, etc.
Basic principles of engineering metrology
Metrology is described as the science of measurement, precision, and accuracy. In other words, it is a method of measurement based on units and predefined standards.
The foreman in the welding department wanted to know what value of allowance to use for a particular section of the shop. A work sampling study was authorized. Only two activity categories were considered: (1) welding and other productive work, (2) personal time, rest breaks and delays. Over a four-week period, where there are 40 hours per week, 161 observations are made at random times. Each observation captured the category of activity of each of 12 welders in the shop section of interest. Results indicated that category 2 constituted 17 % of the total observations.
(a) Can you conclude that realized PFD is 17 % in the factory at 100*(1-0.02) % confidence level with 7% precision?
(b) If a total of 88 work units were produced during the 4 weeks, and all category 1 activity was devoted to producing these units, what was the average time spent on each unit?
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