Exam 17: Statistical Applications in Quality Management

Variation due to the inherent variability in a system of operation is called

TABLE 17-4 A factory supervisor is concerned that the time it takes workers to complete an important production task (measured in seconds)is too erratic and adversely affects expected profits.The supervisor proceeds by randomly sampling 5 individuals per hour for a period of 10 hours.The sample mean and range for each hour are listed below. She also decides that lower and upper specification limit for the critical-to-quality variable should be 10 and 30 seconds, respectively. -Referring to Table 17-4,suppose the supervisor constructs an R chart to see if the variability in collection times is in-control.What is the center line of this R chart?

TABLE 17-9 The manufacturer of canned food constructed control charts and analyzed several quality characteristics.One characteristic of interest is the weight of the filled cans.The lower specification limit for weight is 2.95 pounds.The table below provides the range and mean of the weights of five cans tested every fifteen minutes during a day's production. -Referring to Table 17-9,an chart is to be used for the weight.The lower control limit for this data set is ________,while the upper control limit is ________.

The purpose of a control chart is to eliminate common cause variation.

Special or assignable causes of variation are signaled by individual fluctuations or patterns in the data.

One of the morals of the red bead experiment is

TABLE 17-7 A supplier of silicone sheets for producers of computer chips wants to evaluate her manufacturing process.She takes samples of size 5 from each day's output and counts the number of blemishes on each silicone sheet.The results from 20 days of such evaluations are presented below. -Referring to Table 17-7,an chart is to be used for the number of blemishes.The center line of this chart is located at ________.

TABLE 17-8 Recently,a university switched to a new type of computer-based registration.The registrar is concerned with the amount of time students are spending on the computer registering under the new system.She decides to randomly select 8 students on each of the 12 days of the registration and determine the time each spends on the computer registering.The range,mean,and standard deviation of the times required to register are in the table that follows. -Referring to Table 17-8,an R chart is to be constructed for the time required to register.One way to create the lower control limit involves multiplying the mean of the sample ranges by D₃.For this data set,the value of D₃ is ________.

TABLE 17-5 A manufacturer of computer disks took samples of 240 disks on 15 consecutive days.The number of disks with bad sectors was determined for each of these samples.The results are in the table that follows. -Referring to Table 17-5,a p control chart is to be made for these data.The estimate of the standard error of the proportion of disks with bad sectors is ________.

Which of the following best measures the ability of a process to consistently meet specified customer-driven requirement?

Variation signaled by individual fluctuations or patterns in the data is called

TABLE 17-3 A quality control analyst for a light bulb manufacturer is concerned that the time it takes to produce a batch of light bulbs is too erratic.Accordingly,the analyst randomly surveys 10 production periods each day for 14 days and records the sample mean and range for each day. -Referring to Table 17-3,suppose the analyst constructs an R chart to see if the variability in production times is in-control.What is the lower control limit for this R chart?

TABLE 17-8 Recently,a university switched to a new type of computer-based registration.The registrar is concerned with the amount of time students are spending on the computer registering under the new system.She decides to randomly select 8 students on each of the 12 days of the registration and determine the time each spends on the computer registering.The range,mean,and standard deviation of the times required to register are in the table that follows. -Referring to Table 17-8,an R chart is to be constructed for the time required to register.One way to create the upper control limit involves multiplying the mean of the sample ranges by D₄.For this data set,the value of D₄ is ________.

An in-control process must be achieved before being able to estimate process capability.

CPL > 1 implies that the process mean is more than 3 standard deviation away from the lower specification limit.

TABLE 17-3 A quality control analyst for a light bulb manufacturer is concerned that the time it takes to produce a batch of light bulbs is too erratic.Accordingly,the analyst randomly surveys 10 production periods each day for 14 days and records the sample mean and range for each day. -Referring to Table 17-3,suppose the analyst constructs an chart to see if the production process is in-control.What is the lower control limit (LCL)for this chart?

TABLE 17-10 Below is the number of defective items from a production line over twenty consecutive morning shifts. -Referring to Table 17-10,based on the c chart,it appears that the process is out of control.

TABLE 17-5 A manufacturer of computer disks took samples of 240 disks on 15 consecutive days.The number of disks with bad sectors was determined for each of these samples.The results are in the table that follows. -Referring to Table 17-5,the best estimate of the mean proportion of disks with bad sectors is ________.

The cause of variation that can be reduced only by changing the system is ________ cause variation.

TABLE 17-8 Recently,a university switched to a new type of computer-based registration.The registrar is concerned with the amount of time students are spending on the computer registering under the new system.She decides to randomly select 8 students on each of the 12 days of the registration and determine the time each spends on the computer registering.The range,mean,and standard deviation of the times required to register are in the table that follows. -Referring to Table 17-8,construct an chart for the time required to register.