Question

In: Statistics and Probability

At one engineering firm, several call centers are maintained to track customer complaints. Unfortunately, very few...

At one engineering firm, several call centers are maintained to track customer complaints. Unfortunately, very few employees like this job and therefore there is a lot of employee turnover. This call center uses X-Bar and s charts to track voluntary quits over time. The averages compiled below are from three call centers. The average number is 25 minutes before an employee gets frustrated and quits. The sample size was n = 5 for each month. Use the data below to create one X-Bar chart and one s chart.

Month (Avg. Time) ((s))

January (27.0) ((2.0)) February (27.0) ((2.7)) March (26.5) ((3.0)) April (28.0) ((2.7)) May (25.5) ((2.0)) June (27.5) ((3.0)) July (25.0) ((1.5)) August (25.5) ((1.6)) September (28.0) ((0.5)) October (26.0) ((2.5)) November (26.0) ((4.7)) December (26.5) ((1.3)) January (25.5) ((2.5)) February (25.0) ((6.0)) March (26.5) ((5.5)) April (25.0) ((4.4)) May (28.5) ((2.0)) June (28.0) ((0.5)) July (26.5) ((2.5)) August (24.5) ((1.0))

Create X-Bar and s control charts from this data. Also, calculate the following: X-Double-Bar, s-Bar, UCLx, LCLx, UCLs, and LCLs

Note: single bracket represents “avg.time” and double bracket represents “s”

Solutions

Expert Solution

The X-bar and S chart are obtained in excel by following these steps,

X-bar chart:

Step 1: Write down the data value in excel for X-bar and S. The screenshot is shown below,

Step 2: The X-double bar is obtained by taking average of x-bar column. The screenshot is shown below,

The s bar value is obtained by taking average of S column. The screenshot is shown below,

Step 3: The Upper and lower control limits for the x-bar chart is obtained using the formula,

Where,

The screenshots are shown below,

Step 4: Now, Select the x-bar, UCL and LCL then INSERT > Recommended Charts > XY Scatter > OK. The screenshot for the chart is shown below,

s-chart:

The upper and lower control limits are obtained using the formula,

Where,

The screenshot is shown below,

The s-chart is shown below,

There two possible sample out of control limit in s chart.

The data values are,

Sample X bar s x double bar s bar UCL X-bar LCL X-bar UCL s-bar LCL s-bar
1 27 2 26.4 2.595 30.10307 22.69694 5.420955 0
2 27 2.7 26.4 2.595 30.10307 22.69694 5.420955 0
3 26.5 3 26.4 2.595 30.10307 22.69694 5.420955 0
4 28 2.7 26.4 2.595 30.10307 22.69694 5.420955 0
5 25.5 2 26.4 2.595 30.10307 22.69694 5.420955 0
6 27.5 3 26.4 2.595 30.10307 22.69694 5.420955 0
7 25 1.5 26.4 2.595 30.10307 22.69694 5.420955 0
8 25.5 1.6 26.4 2.595 30.10307 22.69694 5.420955 0
9 28 0.5 26.4 2.595 30.10307 22.69694 5.420955 0
10 26 2.5 26.4 2.595 30.10307 22.69694 5.420955 0
11 26 4.7 26.4 2.595 30.10307 22.69694 5.420955 0
12 26.5 1.3 26.4 2.595 30.10307 22.69694 5.420955 0
13 25.5 2.5 26.4 2.595 30.10307 22.69694 5.420955 0
14 25 6 26.4 2.595 30.10307 22.69694 5.420955 0
15 26.5 5.5 26.4 2.595 30.10307 22.69694 5.420955 0
16 25 4.4 26.4 2.595 30.10307 22.69694 5.420955 0
17 28.5 2 26.4 2.595 30.10307 22.69694 5.420955 0
18 28 0.5 26.4 2.595 30.10307 22.69694 5.420955 0
19 26.5 2.5 26.4 2.595 30.10307 22.69694 5.420955 0
20 24.5 1 26.4 2.595 30.10307 22.69694 5.420955 0

Related Solutions

An airline operates a call center to handle customer questionsand complaints. The airline monitors a...
An airline operates a call center to handle customer questions and complaints. The airline monitors a sample of calls to help ensure that the service being provided is of high quality. Ten random samples of 100 calls each were monitored under normal conditions. The center can be thought of as being in control when these 10 samples were taken. The number of calls in each sample not resulting in a satisfactory resolution for the customer is as follows.5743445659(a)What is an...
An airline operates a call center to handle customer questions and complaints. the airline monitors a...
An airline operates a call center to handle customer questions and complaints. the airline monitors a sample of calls to help ensure that the service being offered is of high quality. The random samples of 100 calls each were monitored under normal conditions. The center can be thought of as being in control when these 10 samples were taken. The number of calls in each sample not resulting in a satisfactory resolution for the customer is as follows: 4 5...
In the Customer and Vendors Centers, you were introduced to several features that QuickBooks uses in...
In the Customer and Vendors Centers, you were introduced to several features that QuickBooks uses in place of ledgers. Features and give examples on how a company might use them. Specifically, I am referring to the following features: Enter Bills, Pay Bills, Create Sales Receipt, Create Invoices, Jobs, Make Deposits, Undeposited Funds, and Receive Payment. What accounting is going on in the background of these features?
An engineering firm with a good track record is known to have a 40% success rate...
An engineering firm with a good track record is known to have a 40% success rate in getting state-government construction contracts. In a recent year, the firm submitted bids on eight construction projects to be funded by the state-government. The bids for different projects are assessed independently of each other. i) CHOOSE which of these probability distributions is most appropriate to describe a random variable X defined as "the number of approved state-government construction contracts bid by the engineering firm...
A large customer call center for a multinational retailer has been in operation for several months,...
A large customer call center for a multinational retailer has been in operation for several months, but has continually failed to meet both customers’ and senior management’s expectations. Your team has been called in to develop a dashboard to help monitor and improve the operations of the call center. What KPIs would you track? Sketch a sample dashboard for this application. Submit the assignment to Dropbox.
A chemical engineering has been working with a local manufacturing firm. For several years the firm...
A chemical engineering has been working with a local manufacturing firm. For several years the firm has been using chemical A as a solvent in their manufacturing process. Chemical A is carcinogenic, although studies supporting this claim have only recently been published. Without taking elaborate safety precautions, workers handling chemical A would be exposed to sufficient amounts to risk cancer. Moreover, the disease takes up to 20 years to manifest itself. The company has tried to implement safety procedures and...
McAdoo & Co. is an engineering firm with offices in several cities in the Carolinas. McAdoo’s...
McAdoo & Co. is an engineering firm with offices in several cities in the Carolinas. McAdoo’s fiscal year-end is December 31, and it prepares financial statements just once a year, at year-end. For bookkeeping purposes, McAdoo has adopted a policy to record payments and collections in advance into asset and liability accounts, respectively. The company’s unadjusted trial balance at December 31, 2020 is shown below. All accounts have normal-side balances. Accounts Payable $   356,210 Accounts Receivable 781,940 Accumulated Depreciation –...
– Problem – Belanger & Associates, PC, is an engineering firm with offices in several cities...
– Problem – Belanger & Associates, PC, is an engineering firm with offices in several cities in the Carolinas. Belanger’s fiscal year-end is December 31, and it prepares financial statements just once a year, at year-end. For bookkeeping purposes, the company has adopted a policy to record payments and collections in advance into asset and liability accounts, respectively. Belanger’s unadjustedtrial balance at December 31, 2018 is shown below. All accounts have normal-side balances. Accounts Payable                                                                     $  602,715 Accounts Receivable                                                                     923,610 Accumulated Depreciation –...
Is rapid economic growth affecting the environment? Several countries that were very poor only a few...
Is rapid economic growth affecting the environment? Several countries that were very poor only a few decades ago have been experiencing rapid economic growth, and at least portions of those countries are approaching levels of economic development that are comparable to those in rich countries. Is the rapid economic growth that has taken place in China, India, and other countries good for the environment or bad?
Baxter has historically maintained a debt-equity ratio of approximately 0.25. The firm enjoys very stable demand...
Baxter has historically maintained a debt-equity ratio of approximately 0.25. The firm enjoys very stable demand for its products, and consequently can borrow at 4.20%, just 20 basis points over the risk-free rate of 4%. Baxter’s tax rate is 40%. Baxter’s current return on equity (rE) is 8% Baxter believes it can increase debt without any serious risk of distress or other costs. With a higher debt-equity ratio of 0.50, it believes its borrowing costs will rise only slightly to...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT