Solved by verified expert :Question
Q-1a. You run a call center and are concerned about customer
support service levels on the Help Desk. You want to know how many
calls per day are handled by your help desk staff. You collect the data
at left over a 75-day period. Use appropriate descriptive statistics
to make sense of this data. Use an appropriate graph also. Explain your
findings so that your non-quantitative partner will understand them. (5
pts.)Sales$1,695,712.62$3,403,862.05$2,710,352.91$529,215.46$663,686.65$2,546,324.34$2,787,046.20$612,696.05$891,822.03$1,124,967.97$909,500.98$2,631,166.88$882,972.65$1,078,573.12$844,320.19$1,849,119.03$3,860,007.32$826,573.88$604,682.87$1,903,611.60$2,356,808.39$2,788,571.96$1,634,878.29$2,371,627.37$2,627,837.96$1,868,116.33$2,236,796.86$1,318,876.23$1,868,097.84$1,695,218.57$2,700,194.42$1,156,049.77$643,858.44Age33.1632.6735.6633.0735.7633.8130.9830.7832.3232.5331.4433.1631.8733.4134.0528.8936.1132.8133.0533.5032.6828.5232.8930.5030.2931.2933.0532.9331.8431.0832.1831.6934.03Growth0.82990.66190.96880.08210.46462.17961.8048-0.0569-0.15770.36642.22561.51580.1413-1.04001.68362.35960.78400.11641.14980.06061.63381.12561.48844.79371.89221.86671.78960.27073.01293.46300.7041-0.15690.7084Income$26,748.51$53,063.79$36,090.14$32,058.07$47,843.42$50,180.97$30,710.08$29,141.70$55,980.15$28,730.88$31,109.23$55,614.12$23,038.43$34,531.72$30,350.36$38,964.94$49,392.77$25,595.69$29,622.61$31,586.10$49,674.56$28,878.98$24,287.08$46,711.24$43,449.81$31,694.45$45,459.22$47,047.34$26,433.24$33,396.66$26,179.36$33,454.64$42,271.50HSCollege73.5988.4673.5479.1884.1893.5078.0270.2970.6763.7476.9182.9565.2173.4980.2287.6085.3065.5980.6280.3879.8581.2470.2287.1080.2175.2977.6285.1874.1881.7073.4173.7278.6517.835031.943918.619820.628435.203241.705728.025015.088210.982913.245819.550020.813516.979632.992022.318524.567030.879017.454518.635638.324923.778016.930019.142930.884326.557028.360019.249035.499418.637541.113017.856626.542629.8734Can
demographic information be helpful in predicting sales at sporting
goods stores? The data at left are monthly sales totals from a random
sample of 33 stores in a large chain of nationwide sporting goods
stores. All stores in the franchise, and thus within the sample, are
approximately the same size and carry the same merchandise. The county, o
r in some cases counties, in which the store draws the majority of its
customers is referred to here as the customer base. For each of the
33 set are:Sales ——Latest one month sales total (dollars)Income —Median family income of customer base (dollars)Age ——–Median age of customer base (years)HS ———-Percentage of customer base with a high school diplomaCollege —Percentage of customer base with a college diplomaGrowth —Annual population growth rate of customer base over the past 10 years._______________________________________________________________________________________Q-2a. Construct a scatter plot, using sales as the dependent variable and median family income as theindependent variable. Discuss the scatter plot. (5 pts.)______________________________________________________________________________________Q-2b. Assuming a linear relationship, use the least-squares method to compute the regression coefficientsb0and b1 and state the regression equation. (5 pts.)______________________________________________________________________________________Q-2c. Interpret the meaning of the Y-intercept, b0, and the slope, b1, in this problem. (5 pts.)______________________________________________________________________________________Q-2d. Compute the coefficient of determination r2, and interpret its meaning. (5 pts.)______________________________________________________________________________________Q-2e. Construct a 95% confidence interval estimate of the population slope and interpret its meaning. ( 5 pts.)Q-3a.
A sample of students from an introductory psychology class were polled
regarding the number of hours they spent studying for the last exam.
All students anonymously submitted the number of hours on a 3 by 5 card.
There were 24 individuals in the one section of the course polled. The
data wasused to make inferences regarding the other students taking
the course. Construct a 95% confidence interval estimate . Explain your
findings so that your non-quantitave partner will understand them. Their
data is below: (5 pts.)20187.511103.57.518192.591491414.517224.510.51558.5820_____________________________________________________________________________________________________________Q-3b.
A sample of Alzheimer’s patients are tested to assess the amount of
time (in minutes) in stage IV sleep. It has been hypothesized that
individuals sufferering from Alzheimer’s Disease may spend less time per
night in the deeper stages of sleep. The number of minutes spent is
Stage IV sleep is recorded for thirty patients (refer to sample data
below of stage IV sleep over a 24 hour period). Compute a 95 percent
confidence interval for this data. What does this information tell you
about a particular individual’s (an Alzheimer’s patient) stage IV sleep?
Explain your findings so that your nonquantitative partner will
understand them. (5 pts.) Stage IV Sleep in Minutes28.537.418.553.261.318.7533.927.173.053.466.020.551.757.2535.633.425.165.355.035.019.2581.544.128.736.532.247.341.739.7518.3_____________________________________________________________________________________________________________Q-3c.
A large retail corportation plans to sample sales receipts of its meat
department to estimate the average size (in dollars) of a customer
purchase. Previous analysis suggest that the standard deviation of the
purchase amount is approximately $50.72. In order to calculate a 95%
confidence interval ofthe total width less than $6.50, how many
sales receipts should the corportion include in the sample? Explain your
findings so that your non-quantitative partner will understand them. (5
pts.)_____________________________________________________________________________________________________________Q-3d.
A survey of 850 workers were asked how much they used the Internet at
work. 578 said they used the internet within limits, and 255 said that
they did not use the Internet at work. Construct a 95% confidence
interval estimate for the proportion of all workers who did not use the
Internet within limits.Explain your findings so that your non-quantitative partner will understand them. (5 pts.)____________________________________________________________________________________________________________ _Q-3e.
You are the designer for your company’s web site. You have data to
indicate that the mean download time for the homepage is 5.8 seconds and
that the standard deviation of download time is 2.1 seconds. If we
assume that the download times are normally distributed, what percent of
users will wait between 4 and 8 seconds for the homepage to download?
Explain your findings so that your non-quantitative partner will
understand them. (5 pts.)Q-4a. You are the manager of a popular
retail store. You want to determine whether the population mean wait
time for customer to check-out has changed in the past month from its
previous population mean value of 4.25 minutes. From past experience,
you can assume that the population is normally distributed with a
population standard deviation of 1.6 minutes. You select a sample of 43
customers wait time to check-out during a one hour period. The sample
mean is 4.75 minutes. Determine whether thereis evidence at the 0.05
level of significance that the population mean wait time to check-out
has changed in the past month from its previous population mean value of
4.25 minutes. Explain your findings utlizing information from the
hypothesis test you conduct. (5 pts.)_______________________________________________________________________________________________________________________Q-4b.
You are the manager of a fast-food restaurant. Based on a sample of
two-hundred fifty drive-through orders, you discovered that orders were
filled correctly 86.5% of the time. In an effort to improve the amount
of orders filled correctly, you developed a new process to fill orders.
After sampling two-hundred fifty orders under this new process, the
results reviled that 225 orders were filled correctly. At the 0.01 level
of significance, can you conclude that the new process population
proportion of orders filledcorrectly is higher than the proportion
of orders filled under the old process? Explain your findings utilizing
information from the test you conduct. (5 pts.)Subcompact320520160160300120520440300170150300180160150400170180260240320260150320180140220Compact515260325470300530265235265320200160330250460Q-5a.
One of the important features of a camera is the battery life as
measured by the number of shots taken until the battery needs to be
recharged. The data at left contain the battery life of 27 subcompact
cameras and 15 compact cameras. Assuming that the population variances
from both types of digital cameras are equal, is there evidence of a
difference in the mean battery life between the two types of
digital cameras at the 95% confidence level? (5 pts.)Price$309.60$307.40$340.30$346.50$298.20$337.80$324.10$313.20$327.80$325.30$308.50$381.30$337.40$346.20$342.40$323.70$329.60$343.60$360.70$348.30Rooms78912691089861310109889119Neighborhood00000000000000111111A
real estate Association in a suburban community would like to study the
relationship between the size of a single-family house (as measured by
number of rooms) and the selling price of the house (in thousands of
dollars). Two different neighborhoods are included in the study, one on
the east side of the community (=0) and the other on the west side (=1).
A random sample of 20 houses was selected with the results given
at left._____________________________________________________________Q-6a.
State the multiple regression equation that predicts the selling
price based on the number of rooms in the neighborhood. (5 pts.)_____________________________________________________________Q-6b. Interpret the regression coefficients. (5 pts.)_____________________________________________________________Q-6c.
Predict the selling price for a house with 10 rooms that is located in
a East-side neighborhood. Explain your findings so that your
nonquantitative partner will understand them. (5 pts.)_____________________________________________________________Q-6d. Compute and interpret the adjusted r2. (5 pts.)Q-7a. The management of a bank in the Caribbean was concerned about the potential loss thatmight occur in the event of a hurricane. The bank estimated that the loss from one of thesestorms could be as much as $120 million including losses due to interrupted service and customerrelations. One project the bank is considering is the installation of an emergency power generatorat its operations headquarters. The cost of the emergency generator is $550,000, and if it isinstalled no losses from this type of storm will be incurred. However, if the generator is notinstalled, there is a 10% chance that a power outage will occur during the next year. If there is anoutage there is a 5% probability that the resulting losses will be very large or approximately $135million in lost earnings. Alternatively it is estimated that there is a 95% probability of only slightlosses of around $1.1 million. Using decision tree analysis, determined whether the bank shouldinstall the new power generator. (5 pts.)Payoff TableDecision (Purchase)Apartment buildingOffice buildingWarehouseGood EconomicConditions50%$80,250$125,250$52,750Poor EconomicConditions50%$33,850-$1,550$40,250An
investor is to purchase one of three types of real estate. The investor
must decide among an apartment building, an office building, and a
warehouse. The future states of nature that will determine how much
profit the investor will make are good economic conditions and
poor economic conditions. The profits that will result from each
decision in the event of each state of nature are shown above._________________________________________________________________Q-8a.
Which investment has the highest EMV and what is the expected value
of perfect information in this problem ? Explain your findings so that
your nonquantitative partner will understand them. (5 pts.)
