Questions from Total Quality Management

Q: The breaking strength of a cable is known to be normally distributed

The breaking strength of a cable is known to be normally distributed with a mean of 4000 kg and a standard deviation of 25 kg. The manufacturer prefers that at least 95%of its product meet a strength...

Q: The specifications for the thickness of nonferrous washers are 1.0

The specifications for the thickness of nonferrous washers are 1.0±0.04 mm. From process data, the distribution of the washer thickness is estimated to be normal with a mean of 0.98 mm and a standard...

Q: A company has been able to restrict the use of electrical power

A company has been able to restrict the use of electrical power through energy conservation measures. The monthly use is known to be normal with a mean of 60,000 kWh (kilowatt-hour) and a standard dev...

Q: A component is known to have an exponential time-to-

A component is known to have an exponential time-to-failure distribution with a mean life of 10,000 hours. (a) What is the probability of the component lasting at least 8000 hours? (b) If the componen...

Q: The time to repair an equipment is known to be exponentially distributed

The time to repair an equipment is known to be exponentially distributed with a mean of 45 min. (a) What is the probability of the machine being repaired within half an hour? (b) If the machine breaks...

Q: A limousine service catering to a large metropolitan area has found that

A limousine service catering to a large metropolitan area has found that the time for a trip (from dispatch to return) is exponentially distributed with a mean of 30 minutes. (a) What is the probabili...

Q: A fast-food restaurant in an urban area experiences a higher

A fast-food restaurant in an urban area experiences a higher traffic rate during the early morning and lunch hours. In order to conduct a customer satisfaction survey, discuss possible sampling proced...

Q: The time to failure of an electronic component can be described by

The time to failure of an electronic component can be described by a Weibull distribution with γ= 0, β= 0.25, and α= 800 hours. (a) Find the mean time to failure. (b) Find the standard deviation of th...

Q: The time to failure of a mechanical component under friction may be

The time to failure of a mechanical component under friction may be modelled by a Weibull distribution with γ= 20 days, β= 0.2, and α = 35 days. (a) What proportion of these components will fail withi...

Q: The diameter of bearings is known to have a mean of 35

The diameter of bearings is known to have a mean of 35 mm with a standard deviation of 0.5 mm. A random sample of 36 bearings is selected. What is the probability that the average diameter of these se...