You are given the following null and alternative hypotheses:
If the true population mean is 4,345, calculate the power of the test. Assume the
population standard deviation is known to be 200 and the sample size is 100.
A) 0.1766
B) 0.3876
C) 0.0808
D) 0.9686
According to data from the Environmental Protection Agency, the average daily water
consumption for a household of four people in the United States is approximately at
least 243 gallons. (Source:
http://www.catskillcenter.org/programs/csp/H20/Lesson3/house3.htm) Suppose a state
agency plans to test this claim using an alpha level equal to 0.05 and a random sample
of 100 households with four people.
State the appropriate null and alternative hypotheses.
A) H0 : μ > 243 Ha : μ ≤ 243
B) H0 : μ < 243 Ha : μ ≥ 243
C) H0 : μ ≤ 243 Ha : μ > 243
D) H0 : μ ≥ 243 Ha : μ < 243
The use of charts and graphs is an example of:
A) descriptive statistics.
B) inferential statistics.
C) estimation.
D) hypothesis testing.
The impact on sampling of increasing the sample size is:
A) the potential for extreme sampling error is reduced.
B) the amount of sampling error is always reduced.
C) the sample mean will always be closer to the population mean.
D) There is no specific relationship between sample size and sampling error.
A corporation has 11 manufacturing plants. Of these, 7 are domestic and 4 are located
outside the United States. Each year a performance evaluation is conducted for 4
randomly selected plants.
What is the probability that a performance evaluation will include exactly 1 plant
outside the United States?
A) 0.4242
B) 0.3776
C) 0.3523
D) 0.4696
A car company is interested in testing to see whether the mean miles that a car engine
will last without changing oil is the same or different depending on which brand of oil
is used. The engineers also wish to control for the type of transmission (manual or
automatic) that is used. To conduct this test, the car company obtains enough engines so
that all four oil brands can be tested in a design that involves no replication. The
following data reflect the miles the engine lasted until problems were encountered. Data
are in thousands of miles.
Assuming that the hypothesis tests are conducted using a significance level equal to
0.05, which of the following statements is true?
A) Based on the data, Oil 1 and Oil 3 give statistically more miles on average than do
the other two oils.
B) The type of transmission does seem to have an impact on the mean miles that an
engine will last.
C) The F-critical value for testing whether blocking is effective is 10.128.
D) All of the above are true.
Each evening, a nationwide retail chain randomly calls 100 of the customers who came
to their store that day to ask whether they were satisfied with the service they had
received. The customers respond yes or no. Suppose the company has found over time
that 8 percent of the customers are not satisfied (“no” answers), what is the 3-sigma
upper and lower control limits for the appropriate control chart?
A) About .053 and .107
B) 0 to about .16
C) -.0.14 to about .16
D) About -1.96 to 1.96
In a local community there are three grocery chain stores. The three have been carrying
out a spirited advertising campaign in which each claims to have the lowest prices. A
local news station recently sent a reporter to the three stores to check prices on several
items. She found that for certain items each store had the lowest price. This survey
didn’t really answer the question for consumers. Thus, the station set up a test in which
20 shoppers were given different lists of grocery items and were sent to each of the
three chain stores. The sales receipts from each of the three stores are recorded in the
data file Groceries.
Based on a significance level of 0.05 and these sample data, test to determine whether
blocking was necessary in this example. Use a test-statistic approach.
A) Since 952.6155 > 1.8673 do not reject H0 and conclude that there is an indication
that blocking was not effective.
B) Since 952.6155 > 1.8673 reject H0 and conclude that there is an indication that
blocking was effective.
C) Since 102.2912 > 1.8673 do not reject H0 and conclude that there is an indication
that blocking was not effective.
D) Since 102.2912 > 1.8673 reject H0 and conclude that there is an indication that
blocking was effective.
College-Pro Painting does home interior and exterior painting. The company uses
inexperienced painters that do not always do a high-quality job. It believes that its
painting process can be described by a Poisson distribution with an average of 4.8
defects per 400 square feet of painting.
What is the probability that a 400-square-foot painted section will have fewer than 6
blemishes?
A) 0.2818
B) 0.3414
C) 0.4857
D) 0.6510
A study was recently conducted to estimate the mean cholesterol for adult males over
the age of 55 years. From a random sample of n = 10 men, the sample mean was found
to be 242.6 and the sample standard deviation was 73.33. To find the 95 percent
confidence interval estimate for the mean, the correct critical value to use is:
A) 1.96
B) 2.2281
C) 2.33
D) 2.2622
An advertising company has developed a new ad for one of the national car
manufacturing companies. The ad agency is interested in testing whether the proportion
of favorable responses to the ad is the same between male adults versus female adults.
It plans on conducting the test using an alpha level equal to 0.05. A sample of 100
adults of each gender will be used in the study. Each person will be asked to view the ad
and indicate whether they find the ad to be “pleasing” or not. Given this, what is the
appropriate null hypothesis?
A) H0 : μ1 = μ2
B) H0 : p1 ≠ p2
C) H0 : 1 = 2
D) H0 : p1 = p2
Consider the following partially completed computer printout for a regression analysis
where the dependent variable is the price of a personal computer and the independent
variable is the size of the hard drive.
Based on the information provided, what is the estimate for the standard error of the
estimate for the regression model?
A) Approximately 690.50
B) About 4,026
C) Just under 376.23
D) 476,800
Construct a 95% confidence interval estimate for the population mean given the
following values:
A) (295.54, 304.56)
B) (297.42, 302.58)
C) (296.52, 303.48)
D) (293.18, 306.82)
Harrison Water Sports has three retail outlets: Seattle, Portland, and Phoenix. The
Seattle store does 50 percent of the total sales in a year, while the Portland store does 35
percent of the total sales. Further analysis indicates that of the sales in Seattle, 20
percent are in boat accessories. The percentage of boat accessories at the Portland store
is 30 and the percentage at the Phoenix store is 25. If a sales dollar is recorded as a boat
accessory, the probability that the sale was made at the Portland store is:
A) slightly greater than 0.43
B) 0.35
C) 0.2425
D) None of the above
At a sawmill in Oregon, a process improvement team measured the diameters for a
sample of 1,500 logs. The following summary statistics were computed:
Given this information, which of the following statements is correct?
A) The distribution of log diameters is symmetric.
B) A log that is over 20 inches in diameter can be considered an outlier.
C) The distribution of log diameters is right-skewed.
D) The distribution is left-skewed.
A pet food producer manufactures and then fills 25-pound bags of dog food on two
different production lines located in separate cities. In an effort to determine whether
differences exist between the average fill rates for the two lines, a random sample of 19
bags from line 1 and a random sample of 23 bags from line 2 were recently selected.
Each bag’s weight was measured and the following summary measures from the
samples are reported:
Management believes that the fill rates of the two lines are normally distributed with
equal variances.
Develop a 95% confidence interval estimate of the true mean difference between the
two lines.
A) -0.1412 ≤ (1 – 2) ≤ -0.0912
B) -0.0974 ≤ (1 – 2) ≤ -0.0026
C) -0.0231 ≤ (1 – 2) ≤ -0.0069
D) -0.0812 ≤ (1 – 2) ≤ -0.0188
The following data reflect the number of customers who test drove new cars each day
for a sample of 20 days at the Redfield Ford Dealership.
Given these data, what is the variance?
A) 0.69
B) Approximately 3.08
C) Approximately 9.52
D) Approximately 181
For a standardized normal distribution, calculate P(-1.28 < z < 1.75).
A) 0.3997
B) 0.4599
C) 0.1404
D) 0.8596
It is assumed that the time customers spend in a record store is uniformly distributed
between 3 and 12 minutes. Based on this information, what is the probability that a
customer will be exactly 7.50 minutes in the record store?
A) 0.1250
B) 0.05
C) Essentially zero
D) 0.111
According to CNN business partner Careerbuilder.com, the average starting salary for
accounting graduates in 2008 was at least $47,413. Suppose that the American Society
for Certified Public Accountants planned to test this claim by randomly sampling 200
accountants who graduated in 2008.
State the appropriate null and alternative hypotheses.
A) H0: μ ≥ $47,413 HA : μ < $47,413
B) H0: μ < $47,413 HA : μ ≥ $47,413
C) H0: μ ≤ $47,413 HA : μ > $47,413
D) H0: μ > $47,413 HA : μ ≤ $47,413
The following probability distribution has been assessed for the number of accidents
that occur in a Midwestern city each day:
Based on this probability distribution, the standard deviation in the number of accidents
per day is:
A) 2.0
B) 1.63
C) 2.65
D) 1.28
Dynamic random-access memory (DRAM) memory chips are made from silicon wafers
in manufacturing facilities through a very complex process called wafer fabs. The
wafers are routed through the fab machines in an order that is referred to as a recipe.
The wafers may go through the same machine several times as the chip is created. The
data file DRAM Chips contains a sample of processing times, measured in fractions of
hours, at a particular machine center for one chip recipe.
Calculate the 80th percentile for processing time.
A) 0.40 minutes
B) 0.35 minutes
C) 0.45 minutes
D) 0.20 minutes
When using Excel’s Histogram option under the Data Analysis tool, the term bins refers
to:
A) the mid-point of each class.
B) the column where the data are located.
C) the upper limits of each class.
D) the lower limits of each class.
A multiple regression is shown for a data set of yachts where the dependent variable is
the price in thousands of dollars.
Given this information, what is the null hypothesis for testing the overall model?
A) H0 : β0 = β1 = β2 = β3 = β4 = 0
B) H0 : β1 = β2 = β3 = β4 = 0
C) H0 : β1 = 0
D) H0 : β0 = 0
The purpose of a pilot sample is:
A) to provide a better idea of what the population mean will be.
B) to help clarify how the sampling process will be performed.
C) to provide an idea of what the population standard deviation might be.
D) to save time and money instead of having to carry out a full sampling plan.
Cross County Bicycles makes two mountain bike models that each come in three
colors. The following table shows the production volumes for last week:
What is the joint probability that a product manufactured is a YZ-99 and brown?
A) 0.2088
B) 0.3819
C) 0.3157
D) 0.1324
Examine the following two-factor analysis of variance table:
Complete the analysis of variance table.
A) MSA = 40.928, F Factor A =3.35, SSB = 85.35, Factor B df = 3, F Factor B = 2.316,
MSAB = 21.859, F Factor AB = 1.8, SSE = 789.29, SSE df = 66, MSE = 12.143
B) MSA = 40.928, F Factor A = 3.35, SSB = 85.35, Factor B df = 4, F Factor B = 2.316,
MSAB = 21.859, F Factor AB = 2.1 SSE = 789.29, SSE df = 66, MSE = 12.143
C) MSA = 40.698, F Factor A = 3.35, SSB = 84.35, Factor B df = 5, F Factor B = 2.316,
MSAB = 21.859, F Factor AB = 2.1, SSE = 789.29, SSE df = 65, MSE = 12.143
D) MSA = 40.698, F Factor A = 3.35, SSB = 84.35, Factor B df = 3, F Factor B =
2.316, MSAB = 21.859, F Factor AB = 1.8, SSE = 789.29, SSE df = 65, MSE = 12.143
In a large sample Mann-Whitney U test in which the sample size from the first
population is 30 and the sample size from the second population is 40, which of the
following is the expected U value if the null hypothesis of equal median values is true?
A) 1,200
B) 70
C) 35
D) 600
In developing a confidence interval estimate for the population mean, which of the
following is true?
A) The larger the sample standard deviation, the wider will be the interval estimate, all
other things being equal.
B) If the population standard deviation is unknown, the appropriate critical value should
be obtained from the t-distribution.
C) The confidence interval developed from a smaller sample size will have a larger
margin of error than one obtained using a larger sample size, all other things being
equal.
D) All of the above are true.
If the p value is less than α in a two-tailed test,
A) the null hypothesis should not be rejected.
B) the null hypothesis should be rejected.
C) a one-tailed test should be used.
D) More information is needed to reach a conclusion about the null hypothesis.