Exam 17: Statistical Applications in Quality Management

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 R chart is to be constructed for the number of blemishes.The lower control limit for this data set is ________.

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,no opportunity appears to be present to render an improvement in the process.

________ causes of variation are correctable without modifying the system.

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.The upper control limit for this data set is ________.

The principal focus of the control chart is the attempt to separate special or assignable causes of variation from common causes of variation.Which causes of variation can be reduced only by changing the system?

One of the morals of the red bead experiment is that variation is part of any process.

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.The center line of this R chart is located at ________.

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,what is the value of the C_pk index?

Which of the following situations suggests a process that appears to be operating out of statistical control?

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,based on the R chart,it appears that the process is out of control.

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 chart is to be used for the time required to register.The center line of this chart is located at ________.

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 R chart is to be constructed for the number of blemishes.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 ________.

TABLE 17-10 Below is the number of defective items from a production line over twenty consecutive morning shifts. -Referring to Table 17-10,a c chart is to be constructed for the number of defective items.The upper control limits is ________.

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,what is the value of the CPL index?

TABLE 17-1 A local newspaper has 10 delivery boys who each deliver the morning paper to 50 customers every day.The owner decides to record the number of papers delivered on time for a 10-day period for one of the delivery boys and construct a p chart to see whether the percentage is too erratic. -Referring to Table 17-1,what is the numerical value of the upper control limit for the p chart?

TABLE 17-2 A political pollster randomly selects a sample of 100 voters each day for 8 successive days and asks how many will vote for the incumbent.The pollster wishes to construct a p chart to see if the percentage favoring the incumbent candidate is too erratic. -Referring to Table 17-2,what is the numerical value of the center line for the p chart?

Larger C_pk indicates larger capability of meeting the requirements.

The control chart

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.The R chart is characterized by which of the following?

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.The lower control limit for this data set is ________.