Exam 10: Quality Control

A design engineer wants to construct a sample mean chart for controlling the service life of a halogen headlamp his company produces. He knows from numerous previous samples that this service life is normally distributed with a mean of 500 hours and a standard deviation of 20 hours. On three recent production batches, he tested service life on random samples of four headlamps, with these results What is the sample mean service life for sample 2?

A c-chart is used to monitor the number of defects per unit for process output.

A shift in the process mean for a measured characteristic would most likely be detected by a

The process capability index (C_pk)may mislead if (I)the process is not stable.(II)the process output is not normally distributed.(III)the process is not centered.

Which of the following is not a step in the control process?

The following data occurs chronologically from left to right The number of runs up and down is:

The approaches to quality assurance are

Process capability compares process variability to the tolerances.

A design engineer wants to construct a sample mean chart for controlling the service life of a halogen headlamp his company produces. He knows from numerous previous samples that this service life is normally distributed with a mean of 500 hours and a standard deviation of 20 hours. On three recent production batches, he tested service life on random samples of four headlamps, with these results If he uses upper and lower control limits of 520 and 480 hours, on what sample(s)(if any)does service life appear to be out of control?

The probability of concluding that assignable variation exists when only random variation is present is (I)the probability of a Type I error.(II)known as the alpha risk.(III)highly unlikely.(IV)the sum of probabilities in the two tails of the normal distribution.

Larger samples will require wider x-bar control limits because there is more data.

The chair of the operations management department at Quality University wants to construct a p-chart for determining whether the four faculty teaching the basic P/OM course are in control with regard to the number of students who fail the course. Accordingly, he sampled 100 final grades from last year for each instructor, with the following results What are the .95 (5 percent risk of Type I error)upper and lower control limits for the p-chart?

A p-chart would be used to monitor

The variation of a sampling distribution isless than the variation of the underlying process distribution.

The sampling distribution can be assumed to be approximately normal even when the underlying process distribution is not normally distributed.

A point which is outside of the lower control limit on an R-chart

The basis for a statistical process control chart is a(the)

The specifications for a product are 6 mm ± 0.1 mm. The process is known to operate at a mean of 6.05 with a standard deviation of 0.01 mm. What is the C_pk for this process?

The primary purpose of statistical process control is to detect a defective product before it is shipped to a customer.

Organizations should work to improve process capability so thatinspection efforts can become more