Questions from Business Statistics

Q: A domestic manufacturer of watches purchases quartz crystals from a Swiss firm

A domestic manufacturer of watches purchases quartz crystals from a Swiss firm. The crystals are shipped in lots of 1000. The acceptance sampling procedure uses 20 randomly selected crystals. a. Const...

Q: Twenty-five samples, each of size 5, were selected

Twenty-five samples, each of size 5, were selected from a process that was in control. The sum of all the data collected was 677.5 pounds. a. What is an estimate of the process mean (in terms of pound...

Q: Twenty-five samples of 100 items each were inspected when a

Twenty-five samples of 100 items each were inspected when a process was considered to be operating satisfactorily. In the 25 samples, a total of 135 items were found to be defective. a. What is an est...

Q: A process sampled 20 times with a sample of size 8 resulted

A process sampled 20 times with a sample of size 8 resulted in x̅ = 28.5 and R̅ = 1.6. Compute the upper and lower control limits for the x̅ and R charts for this process.

Q: Temperature is used to measure the output of a production process.

Temperature is used to measure the output of a production process. When the process is in control, the mean of the process is µ = 128.5 and the standard deviation is σ = .4. a....

Q: A quality control process monitors the weight per carton of laundry detergent

A quality control process monitors the weight per carton of laundry detergent. Control limits are set at UCL = 20.12 ounces and LCL = 19.90 ounces. Samples of size 5 are used for the sampling and insp...

Q: The Goodman Tire and Rubber Company periodically tests its tires for tread

The Goodman Tire and Rubber Company periodically tests its tires for tread wear under simulated road conditions. To study and control the manufacturing process, 20 samples, each containing three radia...

Q: Young Adult magazine states the following hypotheses about the mean age of

Young Adult magazine states the following hypotheses about the mean age of its subscribers. H0: µ = 28 Ha: µ ≠ 28 If the manager conducting the test will permit a .15 probability of making a Type II e...

Q: Over several weeks of normal, or in-control, operation

Over several weeks of normal, or in-control, operation, 20 samples of 150 packages each of synthetic-gut tennis strings were tested for breaking strength. A total of 141 packages of the 3000 tested fa...

Q: An airline operates a call center to handle customer questions and complaints

An airline operates a call center to handle customer questions and complaints. The airline monitors a sample of calls to help ensure that the service being provided is of high quality. Ten random samp...