Statistical Process Control BPS 7e Chapter 31 © 2015 W. H. Freeman and Company

Process In thinking about quality improvement, it is often more natural to speak of processes rather than populations. A process is a chain of activities that turns ______ into ______. population; samples samples; population inputs; outputs outputs; inputs

Process (answer) In thinking about quality improvement, it is often more natural to speak of processes rather than populations. A process is a chain of activities that turns ______ into ______. population; samples samples; population inputs; outputs outputs; inputs

Process A variable that continues to be described by the same distribution when observed over time is said to be in: reverse causality. statistical control. statistical significance. None of the above

Process (answer) A variable that continues to be described by the same distribution when observed over time is said to be in: reverse causality. statistical control. statistical significance. None of the above

Process A __________ is a picture of the stages of a process. A __________ organizes the logical relationships between the inputs and stages of a process and an output. cause-and-effect diagram; flowchart scatterplot; flowchart flowchart; cause-and-effect diagram cause-and-effect diagram; scatterplot

Process (answer) A __________ is a picture of the stages of a process. A __________ organizes the logical relationships between the inputs and stages of a process and an output. cause-and-effect diagram; flowchart scatterplot; flowchart flowchart; cause-and-effect diagram cause-and-effect diagram; scatterplot

Three-Sigma Control Charts To make a three-sigma (3σ) control chart for any statistic Q, one should: take samples from the process at regular intervals and plot the values of the statistic Q against the order in which the samples were taken. draw a center line on the chart at height Q, the mean of the statistic when the process is in control. draw upper and lower control limits on the chart three standard deviations of Q above and below the mean. All of the above

Three-Sigma Control Charts (answer) To make a three-sigma (3σ) control chart for any statistic Q, one should: take samples from the process at regular intervals and plot the values of the statistic Q against the order in which the samples were taken. draw a center line on the chart at height Q, the mean of the statistic when the process is in control. draw upper and lower control limits on the chart three standard deviations of Q above and below the mean. All of the above

Statistical Control True or False: All processes have variation. If the pattern of variation is stable over time, the process is in statistical control. True False

Statistical Control (answer) True or False: All processes have variation. If the pattern of variation is stable over time, the process is in statistical control. True False

What Type of Chart? What type of control chart (or charts) would you use as part of efforts to improve each of the following performance measures in a college admissions office? time to acknowledge receipt of an application percent of admission offers accepted student participation in a healthy meal plan Both A and B

What Type of Chart? (answer) What type of control chart (or charts) would you use as part of efforts to improve each of the following performance measures in a college admissions office? time to acknowledge receipt of an application percent of admission offers accepted student participation in a healthy meal plan Both A and B

Concept _____________ refers to the ability of a process to meet or exceed the requirements placed on it. Inter-item correlation Process tracing Capability None of the above

Concept (answer) _____________ refers to the ability of a process to meet or exceed the requirements placed on it. Inter-item correlation Process tracing Capability None of the above

Control Charts When we measure some quantitative characteristic of the process, we use ________ charts for process control. x and s pie and bar R and p nonparametric

Control Charts (answer) When we measure some quantitative characteristic of the process, we use ________ charts for process control. x and s pie and bar R and p nonparametric

Control Charts A(n) ________ chart is a control chart based on plotting sample proportions from regular samples from a process against the order in which the samples were taken. R μ (mean) p s

Control Charts (answer) A(n) ________ chart is a control chart based on plotting sample proportions from regular samples from a process against the order in which the samples were taken. R μ (mean) p s

p Chart A company is concerned that invoices that remain unpaid after 30 days are damaging relations with vendors. To assess the magnitude of the problem, a manager searches payment records for invoices that arrived in the past 10 months. The average number of invoices is 2875 per month, with relatively little month-to-month variation. Of all these invoices, 960 remained unpaid after 30 days. What is p ? 960*10 / 2875 2875 / 960 960 / 2875*10 960*10 / 2875*10

p Chart (answer) A company is concerned that invoices that remain unpaid after 30 days are damaging relations with vendors. To assess the magnitude of the problem, a manager searches payment records for invoices that arrived in the past 10 months. The average number of invoices is 2875 per month, with relatively little month-to-month variation. Of all these invoices, 960 remained unpaid after 30 days. What is p ? 960*10 / 2875 2875 / 960 960 / 2875*10 960*10 / 2875*10

p Chart A company is concerned that invoices that remain unpaid after 30 days are damaging relations with vendors. To assess the magnitude of the problem, a manager searches payment records for invoices that arrived in the past 10 months. The average number of invoices is 2875 per month, with relatively little month-to-month variation. Of all these invoices, 960 remained unpaid after 30 days. Given that p = 0.33. What is the UCL? 0.33 + (0.33)(0.67) / 2875 0.33 + 2 (0.33)(0.67) / 2875 0.33 − 3 (0.33)(0.67) / 2875 0.33 + 3 (0.33)(0.67) / 2875

p Chart (answer) A company is concerned that invoices that remain unpaid after 30 days are damaging relations with vendors. To assess the magnitude of the problem, a manager searches payment records for invoices that arrived in the past 10 months. The average number of invoices is 2875 per month, with relatively little month-to-month variation. Of all these invoices, 960 remained unpaid after 30 days. Given that p = 0.33. What is the UCL? 0.33 + (0.33)(0.67) / 2875 0.33 + 2 (0.33)(0.67) / 2875 0.33 − 3 (0.33)(0.67) / 2875 0.33 + 3 (0.33)(0.67) / 2875