BUS 67530

X has the following probability distribution P(X).

Compute the expected value of X.
A. 2.5
B. 1.0
C. 1.6
D. 0.6

The weight of a product is normally distributed with a mean of 5 ounces. A randomly selected unit of this product weighs 7.1 ounces. The probability of a unit weighing more than 7.1 ounces is .0014. The production supervisor has lost files containing various pieces of information regarding this process, including the standard deviation. Determine the value of the standard deviation for this process.
A. 1.67
B. 0.70
C. 2.10
D. 0.50

The population of lengths of aluminum-coated steel sheets is normally distributed with a mean of 30.05 inches and a standard deviation of 0.3 inches. What is the probability that the average length of a steel sheet from a sample of 9 units is more than 29.95 inches long?
A. .4602
B. .8413
C. .1587
D. .5397

A local airport keeps track of the percentage of flights arriving within 15 minutes of their scheduled arrivals. The stem-and-leaf plot of the data for one year is below.

What would be the class length for creating the frequency histogram?
A. 1.4
B. 0.8
C. 2.7
D. 1.7
E. 2.3

In performing a one-way ANOVA, the _________ is the between-group variance.
A. MS Error
B. MS Treatment
C. SS Error
D. SS Treatment

According to data from the state blood program, 40 percent of all individuals have group A blood. Suppose that of six randomly selected individuals, three have group A blood. Would you believe the data from the state blood program?
A. Yes, probability is > .05.
B. Yes, probability is < .05.
C. No

The average time an individual reads online national news reports is 49 minutes. Assume the standard deviation is 16 minutes and that the times are normally distributed. For the 10 percent who spend the most time reading national news online, how much time do they spend?
A. > 11.72
B. > 28.52
C. > 86.28
D. > 69.48

Which of the following is a violation of the independence assumption?
A. negative autocorrelation
B. a pattern of cyclical error terms over time
C. positive autocorrelation
D. a pattern of alternating error terms over time
E. All of the other choices are correct.

The average of the squared deviations of the individual population measurement from the population mean is the ___________.
A. standard deviation
B. mean
C. variance
D. median
E. range

The standard deviation of a standard normal distribution is always equal to ____________.
A. 1
B. 0.5
C. 0
D. −1

Joe is considering pursuing an MBA degree. He has applied to two different universities. The acceptance rate for applicants with similar qualifications is 25 percent for University A and 40 percent for University B.
What is the probability that Joe will be accepted at one, and only one, university?
A. 0.50
B. 0.10
C. 0.15
D. 0.30
E. 0.45

Examining all population measurements is called a_____________.
A. census
B. frame
C. sample
D. variable

If a control chart is used correctly and the necessary corrective actions are taken, as the control limits get ____________, the potential quality of the product _____________.
A. looser, increases
B. tighter, decreases
C. tighter, increases
D. None of the other choices is correct.

According to a hospital administrator, historical records over the past 10 years have shown that 20 percent of the major surgery patients are dissatisfied with after-surgery care in the hospital. A scientific poll based on 400 hospital patients has just been conducted. What is the probability that fewer than 64 patients will not be satisfied with the after-surgery care?
A. 47.72%
B. 2.28%
C. 97.72%
D. 95.44%
E. 4.56%

A local country club golf tournament organizer is attempting to estimate the average number of strokes for the 13th hole. On a particular day, 64 players completed the play on the 13th hole, with an average of 4.25 strokes and a population standard deviation of 1.6 strokes. Determine the 95 percent confidence interval for the average number of strokes.
A. [3.94, 4.56]
B. [3.86, 4.64]
C. [4.05, 4.45]
D. [3.92, 4.58]

If we collect data on the number of wins each team in the NFL had during the 2011-12 season, we have _____________ data.
A. cross-sectional
B. time series
C. non-historical
D. survey

You want to estimate the proportion of customers who are satisfied with their experiences at a local supermarket at α = .10 and within .025 of the true value. It has been estimated that p =.85. How large of a sample is needed?
A. 1083
B. 553
C. 71
D. 336

Given a standard deck of cards, what is the probability of drawing a face card, given that it is a red card?
A. 0.115
B. 0.500
C. 0.231
D. 0.462
E. 0.308

An apple juice producer buys all his apples from a conglomerate of apple growers in one northwestern state. The amount of juice obtained from each of these apples is approximately normally distributed with a mean of 2.25 ounces and a standard deviation of 0.15 ounce. 77 percent of the apples will contain at least how many ounces of juice?
A. 2.12
B. 2.38
C. 2.36
D. 2.14

The average life of Canadian women is 73.75 years, and the standard deviation of the life expectancy of Canadian women is 6.5 years. Based on Chebyshev’s Theorem, determine the upper and lower bounds on the average life expectancy of Canadian women such that at least 90 percent of the population is included.
A. [12.09 135.41]
B. [8.75 138.75]
C. [53.20 94.30]
D. [66.38 81.13]
E. [67.25 80.25]

Alternatives 1 and 2 in the following payoff table represent the two possible manufacturing strategies that the EKA manufacturing company can adopt. The level of demand affects the success of both strategies. The states of nature (S_I) represent the levels of demand for the company products. S₁, S₂, and S₃ characterize high, medium, and low demand, with probabilities of .3, .6, and .1, respectively. The payoff values are in thousands of dollars.

The management believes that the weather conditions significantly affect the level of demand. 48 monthly sales reports are randomly selected. These monthly sales reports show 15 months with high demand, 28 months with medium demand, and 5 months with low demand. 12 of the 15 months with high demand had favorable weather conditions. 14 of the 28 months with medium demand had favorable weather conditions. Only 1 of the 5 months with low demand had favorable weather conditions. What is the maximum amount that the company would be willing to pay for perfect information?
A. $95,000
B. $112,000
C. $7,000
D. $24,000
E. $17,000

A Type II error is defined as ________________ H₀, when it should _____________.
A. failing to reject, be rejected
B. failing to reject, not be rejected
C. rejecting, not be rejected
D. rejecting, rejected

A motorcycle manufacturer produces the parts for its vehicles in different locations and transports them to its plant for assembly. In order to keep the assembly operations running efficiently, it is vital that all parts be within specification limits. One important part used in the assembly is the engine camshaft, and one important quality characteristic is the case hardness depth. Specifications state that the hardness depth must be between 3.0 mm and 6.0 mm. To investigate the process, the quality control engineer selected 25 daily subgroups of n = 5 and measured the hardness depth. The process yielded a mean of the means = 4.50 and an average range = 1.01. Calculate the control limits for the X-bar chart.
A. [4.345, 4.655]
B. [3.49, 5.51]
C. [3.917, 5.083]
D. [2.365, 6.635]

The probability of event A occurring given that event B has already occurred is 0.61. The probability of both events occurring is 0.5. What is the probability of event B occurring?
A. 0.305
B. 0.195
C. 0.390
D. 0.820
E. 0.500

The ___________ test is a test for first-order positive autocorrelation.
A. Durbin-Watson
B. MSD
C. MAD
D. multiplicative Winters

The time between breakdowns of an alarm system is exponentially distributed with mean 10 days. What is the probability that there are no breakdowns on a given day?
A. .9048
B. .3679
C. .0952
D. 0.000

The company financial officer was interested in the average cost of PCs that had been purchased in the past six months. She took a random sample of the price of 10 computers, with the following results.
$3,250, $1,127, $2,995, $3,250, $3,445, $3,449, $1,482, $6,120, $3,009, $4,000
What is the first quartile?
A. $1,446.50
B. $2,995.00
C. $3,415.75
D. $3,587.00
E. $4,212.00

______________ is the science of using a sample to make generalizations about the important aspects of a population.
A. Time series analysis
B. Descriptive statistics
C. Random sample
D. Statistical inference

In utility analysis, a utility curve that shows a rapid increase in utility for initial amounts of money followed by a gradual leveling off for a larger amount of money is appropriate for a risk _________ decision maker.
A. seeking
B. averse
C. neutral
D. None of the other choices is correct.

XYZ Company, Annual Data

Based on the information given in the table above, we can conclude that, in general,
A. the forecasting method is underestimating demand.
B. the forecasting method is overestimating demand.
C. we cannot determine whether the predictions are underestimating or overestimating demand.

The time it takes a woman to travel from her apartment to the bus station follows a uniform distribution over the interval from 20 to 30 minutes. If she leaves home at 9:05 a.m., what is the probability that she will get to the station between 9:25 and 9:30 a.m.?
A. 1.0
B. 0
C. 0.5
D. 0.25

An automobile insurance company is in the process of reviewing its policies. The company is considering increasing the premium charged to drivers under 25. According to company records, 35 percent of the insured drivers are under the age of 25. The company records also show that 280 of the 700 insured drivers under the age of 25 have been involved in at least one automobile accident. On the other hand, only 130 of the 1,300 insured drivers 25 years or older have been involved in at least one automobile accident.
An accident has just been reported. What is the probability that the insured driver is under the age of 25?
A. 35%
B. 20.5%
C. 14%
D. 68.3%
E. 40%

A motorcycle manufacturer produces the parts for its vehicles in different locations and transports them to its plant for assembly. To keep the assembly operations running efficiently, it is vital that all parts be within specification limits. One important part used in the assembly is the engine camshaft, and one important quality characteristic is the case hardness depth. Specifications state that the hardness depth must be between 3.0 mm and 6.0 mm. To investigate the process, the quality control engineer selected 25 daily subgroups of n = 5 and measured the hardness depth. The process yielded a mean of the means = 4.50 and an average range = 1.01. Calculate the center line for the X-bar chart.
A. 1.01
B. 4.50
C. 3.49
D. 0.90

If there are 130 values in a data set, how many classes should be created for a frequency histogram?
A. 4
B. 5
C. 6
D. 7
E. 8

In a random sample of 651 computer scientists who subscribed to a web-based daily news update, it was found that the average salary was $46,816 with a population standard deviation of $12,557. Calculate a 91 percent confidence interval for the mean salary of computer scientists.
A. [$25,469, $68,163]
B. [$46,592, $47,040]
C. [$46,157, $47,475]
D. [$46,783, $46,849]
E. [$45,981, $47,650]

Suppose that annual sales for a company were $3.6 million at the beginning of a three-year period and at the end had increased to $6.1 million. Find the geometric growth rate of sales.

If the total sum of squares in a one-way analysis of variance is 25 and the treatment sum of squares is 17, then what is the error sum of squares?

Consider the following partial computer output from a simple linear regression analysis.

Determine the 95 percent confidence interval for the mean value of y when x = 9.00. Givens: ∑x = 129.03 and ∑x² = 1178.547

The HR manager of a major office supply chain is interested in determining whether employee educational level affects knowledge of their job. An exam was given to 120 employees. The results are below.

For each row total, calculate the corresponding percentage.

In a one-way analysis of variance with three treatments, each with five measurements, in which a completely randomized design is used, what is the degrees of freedom for treatments?

A cereal manufacturer is concerned that the boxes of cereal not be underfilled or overfilled. Each box of cereal is supposed to contain 13 ounces of cereal. A random sample of 31 boxes is tested. The average weight is 12.58 ounces, and the standard deviation is 0.25 ounces. Calculate a confidence interval to test the hypotheses at α = .10 and interpret.

The quality control manager for NKA Inc. must decide whether to accept (alternative 1), further analyze (alternative 2), or reject (alternative 3) an incoming shipment (lot) of microchips. The historical data indicate that there is a 30 percent chance that the lot is poor quality (S₁), 50 percent chance that the lot is fair quality (S₂), and 20 percent chance that the lot is good quality (S₃). Assume the following payoff table is available. The values in the payoff table are in thousands of dollars.

What alternative action should be selected according to the expected monetary value criterion?

A paper presented at a recent meeting of higher education researchers compared the type of college freshmen attend and the numbers who drop out. A random sample of freshmen shows the following results.

Calculate the chi-square statistic for this test of independence.

In the past, of all the students enrolled in Basic Business Statistics, 10 percent earned an A, 20 percent earned a B, 30 percent earned a C, 20 percent earned a D, and the remainder failed the course. Dr. Johnson is a new professor teaching Basic Business Statistics for the first time this semester. At the conclusion of the semester, of his 60 students, 10 had earned an A, 20 a B, 20 a C, 5 a D, and 5 received an F. Assume that the class constitutes a random sample. Dr. Johnson wants to know if there is sufficient evidence to conclude that the grade distribution of his class is different from the historical grade distribution. Use α = .05 and determine the appropriate degrees of freedom and the rejection point condition associated with this goodness-of-fit test.

In the past, of all the students enrolled in Basic Business Statistics, 10 percent earned an A, 20 percent earned a B, 30 percent earned a C, 20 percent earned a D, and the remainder failed the course. Dr. Johnson is a new professor teaching Basic Business Statistics for the first time this semester. At the conclusion of the semester, of his 60 students, 10 had earned an A, 20 a B, 20 a C, 5 a D, and 5 received an F. Assume that the class constitutes a random sample. Dr. Johnson wants to know if there is sufficient evidence to conclude that the grade distribution of his class is different from the historical grade distribution. Calculate the chi-square statistic.

A company that fills one-gallon containers of water has four machines. The quality control manager needs to determine whether the average fill for these machines is the same. For a sample of 19 one-gallon containers, we have the following data of fill measures (x) in quarts.
        Machine 1      Machine 2 Machine 3 Machine 4
N       4       6       5       4
       4.03    4.0017  3.974   4.005
S       0.0183  0.0117  0.0182  0.0129

And the following partial ANOVA table.
 
Source    SS     DF     MS      F
Treatment               0.002359  
Error                            
Total     0.010579      

If the 95 percent confidence interval for a mean is from .771 to 1.629, can we conclude that μ = .5, using a 95 percent confidence interval?
A. Yes
B. No

It has been hypothesized that on average employees spend one hour a day playing video games at work. To test this at her company, a manager takes a random sample of 35 employees, who showed a mean time of 55 minutes per day with an assumed population standard deviation of 5 minutes. What is the critical value for testing these hypotheses at α = .01?

Two coffee-vending machines are studied to determine whether they distribute the same amounts. Samples are taken and the number of ounces is recorded for each machine.
Machine A          Machine B
6.10                      5.99
5.95                     6.01
5.98                     5.98
6.01                     5.96
6.00                     6.08
5.95                     5.89
6.02                     6.01
6.04                     6.00
5.99                      5.97
6.06                     6.00

On average, can we conclude that the machines distribute the same amount? Test at α = .05.
A. Reject the null hypothesis.
B. Do not reject the null hypothesis.

A test of driving ability is given to a random sample of 10 student drivers before and after they complete a formal driver education course. Results follow.

Test the hypothesis that there is no difference between the before-class scores and the after-class scores at α = .05.

According to a national survey, the average commuting time for people living in a city with a population of 1 to 3 million is 19.0 minutes. Suppose a researcher lives in a city with a population of 2.4 million and wants to test this claim for her city. Taking a random sample of 20 commuters, she calculates a mean time of 19.346 minutes and a standard deviation of 2.842 minutes. Calculate the appropriate test statistic to test the hypotheses.

When we test H₀: μ₁μ₂, H_A: μ₁ > μ₂ at α = .10, where = 77.4, = 72.2, s₁ = 3.3, s₂ = 2.1, n₁ = 6, and n₂ = 6, can we reject the null hypothesis (using critical value rules)? (Assume equal variances.)