Exam 22: Quality Control

A manufacturer of a particular grade of copper tubing collects data on the number of flaws occurring in 500 foot coils.Suppose they sample a total of 40 coils to initiate control charting.The average number of defects per coil is 2.5.The lower and upper control limits for the appropriate control chart for these data are ________________________ .

A manufacturer of a particular grade of copper tubing collects data on the number of flaws occurring in 500 foot coils.Suppose they sample a total of 40 coils to initiate control charting.The average number of defects per coil is 2.5.The appropriate control chart for these data is the ________________________ .

A company that manufactures health food snacks produces low sodium rice chips.To monitor the process for sodium levels, chips are selected periodically and the amount of sodium (mg) measured.For each of thirty samples consisting of 8 chips, the mean and range in sodium content is determined.The average of the means across all samples is 55 mg and the average range is 2.2 mg.The lower and upper control limits for the x-bar chart are ________________________ .

By design, a required dimension on a part is 0.575 inches plus or minus 0.008 inches.Assume that the process producing this part is stable with a mean of 0.579 inches and standard deviation of 0.002 inches.What is the C_p index?

Machine oil is used by clothing manufacturers to lubricate and protect sewing machines.A company that produces machine oil must ensure that the viscosity of its product meets customer requirements.Consequently, the viscosity of every batch of oil produced is measured.Suppose that the process mean is 101 cP and the process standard deviation is 1.50 cP.What is the C_pk index if the customer specifications require viscosity of the machine oil to be 100cP ± 4.5 cP?

Machine oil is used by clothing manufacturers to lubricate and protect sewing machines.A company that produces machine oil must ensure that the viscosity of its product meets customer requirements.Consequently, the viscosity of every batch of oil produced is measured.Suppose that the process mean is 101 cP and the process standard deviation is 1.50 cP.What type of chart should be used to ensure the process remains in control?

A producer of specialty products uses a variety of natural and man-made materials to make unique countertops for kitchens and baths.One product line mixes concrete and natural river stone to make countertops that are polished to a high shine revealing unique patterns.Occasionally coarse sand will result in undesirable pitting and rough spots on surfaces.Consequently, as part of its quality control efforts, 8 by 4 foot polished slabs are checked periodically for imperfections.For each slab inspected the number of imperfections (pits, rough spots, etc.) is recorded.What type of control chart should be used for these data?

A company that manufactures health food snacks produces low sodium rice chips.To monitor the process for sodium levels, chips are selected periodically and the amount of sodium (mg) measured.For each of thirty samples consisting of 8 chips, the mean and range in sodium content is determined.The average of the means across all samples is 55 mg and the average range is 2.2 mg.The estimated process standard deviation () is ________________________ .

An automatic filling process is used to dispense hand sanitizer into small purse size bottles.The target weight is 75 ml.The company has initiated control charting to stabilize and improve the automatic filling process.For each of twenty-five samples consisting of four bottles, the contents were measured and the mean weight and range were determined.The average of the means across all samples was found to be 72.5 ml.and the average range was 2.75 ml.The control limits for the R chart are ________________________ .

In order to achieve higher levels of customer satisfaction, a company initiates monitoring the complaint resolution process of its customer service representatives.As a first step, the company decides to collect data on the number of unanswered calls out of the first 250 incoming calls to its call center made each day.At the end of monitoring 25 days, it was found that a total of 500 incoming calls went unanswered.The control limits for the p-chart of these data are ________________________ .

A company that manufactures health food snacks produces low sodium rice chips.To monitor the process for sodium levels, chips are selected periodically and the amount of sodium (mg) measured.For each of thirty samples consisting of 8 chips, the mean and range in sodium content is determined.The average of the means across all samples is 55 mg and the average range is 2.2 mg.The lower and upper control limits for the R chart are ________________________ .

Which of the following statements is false regarding control charts?

An importer of decorative ceramic tile samples 50 tiles each day from incoming shipments.Some tiles are cracked or broken before or during transit, rendering them useless scrap.Sampling from incoming shipments for 30 days reveals that a total of 250 tiles are cracked or broken.The centerline on the p chart for these data is ________________________ .

A paper products manufacturer coats paper with a thin film of wax.To initiate control charting, data are collected on the thickness of the coating (measured in mm) by taking twenty-five samples each of size five.The appropriate control chart for these data is the ________________________ .

A producer of specialty products uses a variety of natural and man-made materials to make unique countertops for kitchens and baths.One product line mixes concrete and natural river stone to make countertops that are polished to a high shine revealing unique patterns.Occasionally coarse sand will result in undesirable pitting and rough spots on surfaces.Consequently, as part of its quality control efforts, 8 by 4 foot polished slabs are checked periodically for imperfections.For each slab inspected the number of imperfections (pits, rough spots, etc.) is recorded.If the average number of imperfections per 8 by 4 foot polished slab is 2.6, the control limits for the appropriate control chart are ________________________ .

An automatic filling process is used to dispense hand sanitizer into small purse size bottles.The target weight is 75 ml.The company has initiated control charting to stabilize and improve the automatic filling process.For each of twenty-five samples consisting of four bottles, the contents were measured and the mean weight and range were determined.The average of the means across all samples was found to be 72.5 ml.and the average range was 2.75 ml.The estimate of the process standard deviation is ________________________ .

An importer of decorative ceramic tile samples 50 tiles each day from incoming shipments.Some tiles are cracked or broken before or during transit, rendering them useless scrap.Sampling from incoming shipments for 30 days reveals that a total of 250 tiles are cracked or broken.The lower and upper control limits on the p chart for these data are ________________________ .

By design, a required dimension on a part is 0.575 inches plus or minus 0.008 inches.Assume that the process producing this part is stable with a mean of 0.579 inches and standard deviation of 0.002 inches.The specification limits for this part are ________________________ .

Machine oil is used by clothing manufacturers to lubricate and protect sewing machines.A company that produces machine oil must ensure that the viscosity of its product meets customer requirements.Consequently, the viscosity of every batch of oil produced is measured.Suppose that the process mean is 101 cP and the process standard deviation is 1.50 cP.What are the limits for a runs chart to be used to see that the process remains control?

An automatic filling process is used to dispense hand sanitizer into small purse size bottles.The target weight is 75 ml.The company has initiated control charting to stabilize and improve the automatic filling process.For each of twenty-five samples consisting of four bottles, the contents were measured and the mean weight and range were determined.The average of the means across all samples was found to be 72.5 ml.and the average range was 2.75 ml.The control limits for the X-bar chart are ________________________ .