Exam 17: Statistical Applications in Quality Management

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 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 lower control limit for the p chart?

TABLE 17-6 The maker of a packaged candy wants to evaluate the quality of her production process. On each of 16 consecutive days, she samples 600 bags of candy and determines the number in each day's sample that she considers to be of poor quality. The data that she developed follow. -Referring to Table 17-6, a p control chart is to be constructed for these data. The center line for the chart should be 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. She also decides that the upper specification limit is 10 blemishes. -Referring to Table 17-7, what percentage of the chips will fall below the upper specification limit?

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. She also decides that the upper specification limit is 10 blemishes. -Referring to Table 17-7, an R chart is to be constructed for the number of blemishes. The center line of this R chart is located at ________.

TABLE 17-6 The maker of a packaged candy wants to evaluate the quality of her production process. On each of 16 consecutive days, she samples 600 bags of candy and determines the number in each day's sample that she considers to be of poor quality. The data that she developed follow. -Referring to Table 17-6, the estimate of the proportion of poor quality bags of candy is ________.

C_pk > 1 indicates that the process average is exactly 3 standard deviations away from the closest specification limit.

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, there appears to be a special cause of variation in the process.

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

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. She also decides that the upper specification limit is 10 blemishes. -Referring to Table 17-7, what is the value of the CPU index?

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

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. She also decides that the upper specification limit is 10 blemishes. -Referring to Table 17-7, what is the value of d₂ factor?

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 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 center line for the p chart?

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

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 center line of this R chart?

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

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 average of the sample ranges by D₃. For this data set, the value of D₃ is ________.

Larger C_pk indicates larger capability of meeting the requirements.

The p chart is a control chart used for monitoring the proportion of items in a batch that meet given specifications.

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, which expression best characterizes the p chart?