Download FINAL EXAM REVIEW

FINAL EXAM REVIEW
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Which of the following is not true of statistics?
A) Statistics involves collecting and summarizing data.
B) Statistics is used to draw conclusions using data.
C) Statistics is used to answer questions with 100% certainty.
D) Statistics can be used to organize and analyze information.
Provide an appropriate response.
2) True or False: Experiments assist the researcher in isolating the causes of the relationships that exist between
two variables.
A) False
B) True
3) The government of a town needs to determine if the city's residents will support the construction of a new town
hall. The government decides to conduct a survey of a sample of the city's residents. Which one of the following
procedures would be most appropriate for obtaining a sample of the town's residents?
A) Survey every 5th person who walks into city hall on a given day.
B) Survey the first 300 people listed in the town's telephone directory.
C) Survey a random sample of employees at the old city hall.
D) Survey a random sample of persons within each geographic region of the city.
Determine the sampling technique which is used.
4) Thirty-five math majors, 43 music majors and 26 history majors are randomly selected from 496 math majors,
278 music majors and 336 history majors at the state university. What sampling technique is used?
A) systematic
B) stratified
C) convenience
D) cluster
E) random
Provide an appropriate response.
5) An experiment in which the experimental unit (or subject) does not know which treatment he or she is receiving
is called a ________________ .
A) randomized block design
B) double-blind experiment
C) single-blind experiment
D) matched-pairs design
1
6) A salesman boasts to a farmer that his new fertilizer will increase the yield of the farmer's crops by 15%. The
farmer wishes to test the effects of the new fertilizer on her corn yield. She has four equal sized plots of land
one with sandy soil, one with rocky soil, one with clay-rich soil, and one with average soil. She divides each
of the four plots into three equal sized portions and randomly labels them A, B and C. The four A portions are
treated with her old fertilizer. The four B portions are treated with the new fertilizer. The four C portions
receive no fertilizer. At harvest time, the corn yield is recorded for each section of land. What is the claim she is
testing?
A) The total yield increased at least 15%.
B) The average soil field had at least a 15% increase in yield.
C) The A sections had at least a 15% increase in yield.
D) The new fertilizer yielded at least a 15% improvement.
7) A drug company wanted to test a new depression medication. The researchers found 700 adults aged 25-35 and
randomly assigned them to two groups. The first group received the new drug, while the second received a
placebo. After one month of treatment, the percentage of each group whose depression symptoms decreased
was recorded and compared. What is the response variable in this experiment?
A) the 700 adults aged 25-35
B) the one month treatment time
C) the percentage who had decreased depression symptoms
D) the type of drug (medication or placebo)
8) A medical journal published the results of an experiment on anxiety. The experiment investigated the effects of
a controversial new therapy for anxiety. Researchers measured the anxiety levels of 75 adult women who suffer
moderate conditions of the disorder. After the therapy, the researchers again measured the women's anxiety
levels. The differences between the the pre- and post-therapy anxiety levels were reported. What is the
treatment in this experiment?
A) the 75 adult women who suffer from anxiety
B) the therapy
C) the differences between the the pre- and post-therapy anxiety levels
D) the disorder (anxiety or no anxiety)
Determine what type of observational study is described. Explain.
9) Researchers wanted to determine whether there was an association between high blood pressure and the
suppression of emotions. The researchers looked at 1800 adults enrolled in a Health Initiative Observational
Study. Each person was interviewed and asked about their response to emotions. In particular they were asked
whether their tendency was to express or to hold in anger and other emotions. The degree of suppression of
emotions was rated on a scale of 1 to 10. Each person's blood pressure was also measured. The researchers
analyzed the results to determine whether there was an association between high blood pressure and the
suppression of emotions.
A) retrospective; Individuals are asked to look back in time.
B) cross-sectional; Information is collected at a specific point in time.
C) cohort; Individuals are observed over a long period of time.
2
Determine whether the underlined value is a parameter or a statistic.
10) A study of 1600 college students in the city of Pemblington found that 10% had been victims of violent crimes.
A) statistic
B) parameter
Classify the variable as qualitative or quantitative.
11) the numbers on the shirts of a boy's football team
A) quantitative
B) qualitative
Determine whether the quantitative variable is discrete or continuous.
12) the speed of a car on a Boston tollway during rush hour traffic
A) continuous
B) discrete
Determine the level of measurement of the variable.
13) an officer's rank in the military
A) interval
B) ordinal
C) nominal
D) ratio
Explain what is misleading about the graphic.
14)
A) The trend is depicted in the wrong direction.
C) The graphic is not misleading.
B) The horizontal label is incomplete.
D) The vertical scale does not begin at zero.
3
The bar graph shows the number of tickets sold each week by the garden club for their annual flower show.
15) During which week was the fewest number of tickets sold?
A) week 4
B) week 2
C) week 6
D) week 5
Provide an appropriate response.
16) A two-pound bag of assorted candy contained 100 caramels, 83 mint patties, 93 chocolate squares, 80 nut
clusters, and 79 peanut butter taffy pieces. To create a pie chart of this data, the angle for the slice representing
each candy type must be computed. What is the degree measure of the slice representing the mint patties
rounded to the nearest degree?
A) 52°
B) 69°
C) 5°
D) 19°
4
17) Each year advertisers spend billions of dollars purchasing commercial time on network sports television. In the
first 6 months of 1988, advertisers spent $1.1 billion. A recent article listed the top 10 leading spenders (in
millions of dollars):
Company A $73.1
Company B 62.2
Company C 57.5
Company D 55.5
Company E 30.6
Company F $25.2
Company G 24.3
Company H 21.4
Company I
23.4
Company J
20.3
Calculate the mean amount spent.
A) 410.47 million dollars
C) 20.26 million dollars
Compute the range for the set of data.
18) 5, 20, 2, 15, 10
A) 18
B) 52.80 million dollars
D) 39.35 million dollars
B) 2
C) 20
D) 5
Provide an appropriate response.
19) For the following data, approximate the mean weekly grocery bill.
Bill (in dollars) Frequency
135-139
10
140-144
13
145-149
16
150-154
18
155-159
11
A) $147.50
B) $145.50
C) $146.00
20) Find the z-score for the value 60, when the mean is 86 and the standard deviation is 8.
A) z = -3.25
B) z = 0.60
C) z = -0.60
5
D) $149.50
D) z = -3.37
21) The following is a sample of 19 November utility bills (in dollars) from a neighborhood.What is the largest bill
in the sample that would not be considered an outlier?
52, 62, 66, 68, 72, 74, 76, 76, 76, 78, 78, 82, 84, 84, 86, 88, 92, 96, 110
A) $88
B) $95
C) $96
D) $86
22) In interpreting a boxplot of a data set we note that the median is to the left of the center of the box and the right
line is longer than the left line. We can conclude that
A) The data is symmetric.
B) The data is skewed left.
C) Skewness or symmetry cannot be determined by a box plot.
D) The data is skewed right.
23) The percentage of measurements that are above the 39th percentile is
A) 71%
B) 61%
C) 39%
D) cannot determine
24) Health care issues are receiving much attention in both academic and political arenas. A sociologist recently
conducted a survey of citizens over 60 years of age whose net worth is too high to qualify for government health
care but who have no private health insurance. The ages of 25 uninsured senior citizens were as follows:
68 73 66 76 86 74 61 89 65 90 69 92 76
62 81 63 68 81 70 73 60 87 75 64 82
Find Q2 of the data.
A) 65.5
B) 73
C) 72
25) The following data are the yields, in bushels, of hay from a farmer's last 10 years:
375, 210, 150, 147, 429, 189, 320, 580, 407, 180.
Find the IQR.
A) 253
B) 265
C) 279
6
D) 74
D) 227
26) A student receives test scores of 62, 83, and 91. The student's term project score is 88 and her homework score is
76. Each test is worth 20% of the final grade, the term project is 25% of the final grade, and the homework grade
is 15% of the final grade. What is the student's mean score in the class?
A) 76.6
B) 80.0
C) 80.6
D) 83.3
27) For the following data set, approximate the sample standard deviation of commuting times per day.
Commute (in min) Frequency
50-52
5
53-55
8
56-58
12
59-61
13
62-64
11
A) 3.9 min
B) 55.7 min
C) 2.5 min
D) 6.6 min
28) True or False: The variance of a population is the arithmetic average of the squared deviations about the
population mean.
A) False
B) True
Find the sample standard deviation.
29) 14, 15, 12, 11, 12, 16, 13, 16, 18, 18
A) 2.0
B) 2.5
C) 1.6
D) 2.3
Provide an appropriate response.
30) The scores from a state standardized test have a mean of 80 and a standard deviation of 10. The distribution of
the scores is roughly bell shaped. Use the Empirical Rule to find the percentage of scores that lie between 60 and
80.
A) 34%
B) 47.5%
C) 95%
D) 68%
7
31) At a tennis tournament a statistician keeps track of every serve. The statistician reported that the mean serve
speed of a particular player was 102 miles per hour (mph) and the standard deviation of the serve speeds was
10 mph. If nothing is known about the shape of the distribution, give an interval that will contain the speeds of
at least eight-ninths of the player's serves.
A) 82 mph to 122 mph
B) 132 mph to 162 mph
C) 62 mph to 142 mph
D) 72 mph to 132 mph
32) The number of students enrolled in a physics class for the last ten semesters are listed below. Find the median
number of students.
65 66 67 66 67 70 67 70 71 68
A) 68 students
B) 70 students
C) 67 students
D) 66 students
33) Describe the shape of the histogram. The data set: Pick-Three lottery results for 10 consecutive weeks
3 6 7 6 0 6 1 7 8 4
1 5 7 5 9 1 5 3 9 9
2 2 3 0 8 8 4 0 2 4
A) skewed to the right
B) skewed to the left
C) uniform
D) symmetric
34) Find the equation of the regression line for the given data.
x
-5 -3 4 1 -1 -2 0 2 3 -4
y
-10 -8 9 1 -2 -6 -1 3 6 -8
^
B) y = 2.097x + 0.552
^
^
D) y= 2.097x - 0.552
A) y = -0.552x + 2.097
^
C) y = 0.522x - 2.097
35) In order for a company's employees to work for the foreign office, they must take a test in the language of the
country where they plan to work. The data below show the relationship between the number of years that
employees have studied a particular language and the grades they received on the proficiency exam. What is
the best predicted value for y given x = 1.5?
Number of years, x
3
4
4
5
3
6
2
7
3
Grades on test, y
61 68 75 82 73 90 58 93 72
A) 59
B) 57
C) 53
D) 55
8
^
36) The regression line for the given data is y = 6.91x + 46.26. Determine the residual of a data point for which x = 6
and y = 90.
Number of years, x
3
4
4
5
3
6
2
7
3
Grades on test, y
61 68 75 82 73 90 58 93 72
A) 87.72
B) 2.28
C) 177.72
D) -662.16
37) True or False: A doctor wishes to determine the relationship between a male's age and that male's total
cholesterol level. He tests 200 males and records each male's age and that male's total cholesterol level. The
males cholesterol level is the predictor variable?
A) True
B) False
38) The data below are the final exam scores of 10 randomly selected calculus students and the number of hours
they slept the night before the exam. Calculate the linear correlation coefficient.
Hours, x
8 10 7 13 7
9
9
10 11 8
Scores, y
60 75 55 83 61 73 80 85 85 66
A) 0.761
B) 0.991
C) 0.847
D) 0.654
Compute the linear correlation coefficient between the two variables and determine whether a linear relation exists.
39) x 10 11 16 9 7 15 16 10
y 96 51 62 58 89 81 46 51
A) r = -0.335; linear relation exists
B) r = -0.335; no linear relation exists
C) r = -0.284; no linear relation exists
D) r = 0.462; linear relation exists
9
Provide an appropriate response.
40) The probability that event A will occur is P(A) =
Number of successful outcomes
Total number of all possible outcomes
A) False
B) True
41) True or False: Mutually exclusive events are not disjoint events.
A) True
B) False
42) True or False: Mutually exclusive events are always independent.
A) True
B) False
Provide an appropriate response. Express your answer as a simplified fraction unless otherwise noted.
43) True or False: Conditional probabilities leave the sample space the same when considering sequential events.
A) True
B) False
Evaluate the factorial expression.
400!
44)
399!
A) 400
B) 399
C) 1
10
D) 159,600
Find the indicated probability.
45) Suppose that the sample space is S = {a, b, c, d, e, f, g, h, i, j} and that outcomes are equally likely. Find the
probability of the event F = "a vowel".
A) 3
B) 0.2
C) 0.33
D) 0.3
Solve the problem.
46) There are 12 runners in a race. In how many ways can the first, second, and third place finishes occur? (Assume
there are no ties.)
A) 1320
B) 218
C) 1324
D) 220
Provide an appropriate response.
47) A club elects a president, vice-president, and secretary-treasurer. How many sets of officers are possible if
there are 12 members and any member can be elected to each position? No person can hold more than one
office.
A) 660
B) 1320
C) 440
D) 11,880
Find the value of the combination.
48) 11C8
A) 3,326,400
B) 12
C) 990
Provide an appropriate response.
49) How many distinct arrangements can be formed from all the letters of "students"?
A) 1680
B) 10,080
C) 40,320
11
D) 165
D) 720
50) A group consists of 6 men and 5 women. Four people are selected to attend a conference. In how many ways
can 4 people be selected from this group of 11? In how many ways can 4 men be selected from the 6 men? Find
the probability that the selected group will consist of all men.
1
1
1
1
A) 330; 15;
B) 7920; 360;
C) 330; 15;
D) 330; 15;
1,814,400
22
22
15,840
Provide an appropriate response. Express your answer as a simplified fraction unless otherwise noted.
51) Assume that P(A) = 0.7 and P(B) = 0.2. If A and B are independent, find P(A and B).
A) 0.90
B) 0.76
C) 1.00
D) 0.14
Provide an appropriate response.
52) CampusFest is a student festival where local businesses come on campus to sell their goods to students at vastly
reduced prices. As part of a give-away promotion, a local cellular phone company gave away 500 cellular
phones to students who signed up for their calling service. Unbeknownst to the company is that 20 of these
cellular phones were faulty and will cause a small explosion when dialed outside the local calling area. Suppose
you and your roommate each received one of the giveaway phones. Find the probability that both of you
received faulty phones.
A) 0.00152
B) 0.0016
C) 0.03848
D) 0.08
53) You toss a fair coin 5 times. What is the probability of at least one head?
A) 0.5000
B) 0.9688
C) 0.0313
D) 0.7500
54) Two dice are rolled. What is the probability of having both faces the same (doubles) or a total of 4 or 10? Round
to the nearest hundredth.
A) 0.06
B) 0.33
C) 0.15
D) 0.28
12
55) The complement of 4 heads in the toss of 4 coins is
A) Three heads
B) All tails
C) At least one tail
D) Exactly one tail
56) The table below represents a random sample of the number of deaths per 100 cases for a certain illness over
time. If a person infected with this illness is randomly selected from all infected people, find the probability that
the person lives 3-4 years after diagnosis. Express your answer as a simplified fraction and as a decimal.
Years after Diagnosis Number deaths
1-2
15
3-4
35
5-6
16
7-8
9
9-10
6
11-12
4
13-14
2
15+
13
1
35
35
7
; 0.029
; 0.35
; 0.538
; 0.058
A)
B)
C)
D)
35
100
65
120
57) A single die is rolled twice. The set of 36 equally likely outcomes is {(1, 1), (1, 2), (1, 3), (1, 4), (1, 5), (1, 6), (2, 1),
(2, 2), (2, 3), (2, 4), (2, 5), (2, 6), (3, 1), (3, 2), (3, 3), (3, 4), (3, 5), (3, 6), (4, 1), (4, 2), (4, 3), (4, 4), (4, 5), (4, 6), (5, 1),
(5, 2), (5, 3), (5, 4), (5, 5), (5, 6), (6, 1), (6, 2), (6, 3), (6, 4), (6, 5), (6, 6)}. Find the probability of getting two numbers
whose sum is less than 13.
1
1
A) 0
B)
C)
D) 1
4
2
58) Classify the statement as an example of classical probability, empirical probability, or subjective probability. In
1
one state lottery, a person selects a 4-digit number. The probability of winning this state's lottery is
.
10,000
A) empirical probability
B) subjective probability
13
C) classical probability
Classify the following random variable according to whether it is discrete or continuous.
59) the speed of a car on a New York tollway during rush hour traffic
A) continuous
B) discrete
Provide an appropriate response.
60) In a recent survey, 66% of the community favored building a health center in their neighborhood. If 14 citizens
are chosen, find the probability that exactly 9 of them favor the building of the health center.
A) 0.216
B) 0.643
C) 0.015
D) 0.660
61) A psychic network received telephone calls last year from over 1.5 million people. A recent article attempts to
shed some light onto the credibility of the psychic network. One of the psychic network's psychics agreed to
take part in the following experiment. Five different cards are shuffled, and one is chosen at random. The
psychic will then try to identify which card was drawn without seeing it. Assume that the experiment was
repeated 60 times and that the results of any two experiments are independent of one another. If we assume that
the psychic is a fake (i.e., they are merely guessing at the cards and have no psychic powers), how many of the
60 cards do we expect the psychic to guess correctly?
A) 0
B) 12
C) 5
D) 11
62) An Apple Pie Company knows that the number of pies sold each day varies from day to day. The owner
believes that on 50% of the days she sells 100 pies. On another 25% of the days she sells 150 pies, and she sells
200 pies on the remaining 25% of the days. To make sure she has enough product, the owner bakes 200 pies
each day at a cost of $1.50 each. Assume any pies that go unsold are thrown out at the end of the day. If she sells
the pies for $5 each, find the probability distribution for her daily profit.
A)
B)
C)
D)
Profit P(profit)
Profit P(profit)
Profit P(profit)
Profit P(profit)
$500
0.5
$350
0.5
$300
0.5
$200
0.5
$750
0.25
$525
0.25
$550
0.25
$450
0.25
$1000 0.25
$700
0.25
$800
0.25
$700
0.25
14
63) Calculate the mean for the discrete probability distribution shown here.
x
3
6
7
11
P(x) 0.15 0.19 0.26 0.4
A) 27
B) 1.9525
C) 7.81
D) 6.75
64) A lab orders a shipment of 100 rats a week, 52 weeks a year, from a rat supplier for experiments that the lab
conducts. Prices for each weekly shipment of rats follow the distribution below:
Price
$10.00
$12.50
$15.00
Probability
0.3
0.2
0.5
How much should the lab budget for next year's rat orders assuming this distribution does not change. (Hint:
find the expected price.)
A) $676.00
B) $13.00
C) $3,515,200.00
D) $1300.00
65) The random variable x represents the number of tests that a patient entering a clinic will have along with the
corresponding probabilities. Find the mean and standard deviation for the random variable x.
x P(x)
3
0
17
1
5
17
2
6
17
3
2
17
4
1
17
A) mean: 2.52; standard deviation: 1.93
C) mean: 1.59; standard deviation: 3.72
B) mean: 1.59; standard deviation: 1.09
D) mean: 3.72; standard deviation: 2.52
15
66) The diameter of ball bearings produced in a manufacturing process can be explained using a uniform
distribution over the interval 3.5 to 5.5 millimeters. What is the probability that a randomly selected ball bearing
has a diameter greater than 4.1 millimeters?
A) 0.4556
B) 2
C) 0.7
D) 0.7455
67) Find the area under the standard normal curve between z = -1.5 and z = 2.5.
A) 0.9831
B) 0.9270
C) 0.6312
D) 0.7182
Suppose that prices of a certain model of new homes are normally distributed with a mean of $150,000. Find the
percentage of buyers who paid:
68) less than $148,400 if the standard deviation is $800.
A) 95%
B) 97.5%
C) 47.5%
D) 2.5%
Use a normal probability plot to asses whether the sample data could have come from a population that is normally
distributed.
69) The following data represent a random sample of the number of shares of a pharmaceutical company's stock
traded for 20 days in 2000.
4.32 9.24 10.74 7.86 14.18
5.63 10.03 9.28 12.44 13.59
4.58 8.88 11.93 7.09 27.88
8.05 10.48 4.62 7.58 11.22
A) normally distributed
B) not normally distributed
Provide an appropriate response.
70) A local concert center reports that it has been experiencing a 15% rate of no-shows on advanced reservations.
Among 150 advanced reservations, find the probability that there will be fewer than 20 no-shows.
A) 0.3187
B) 0.2451
C) 0.7549
D) 0.7967
16
71) The amount of soda a dispensing machine pours into a 12 ounce can of soda follows a normal distribution with
a standard deviation of 0.32 ounce. Every can that has more than 12.80 ounces of soda poured into it causes a
spill and the can needs to go through a special cleaning process before it can be sold. What is the mean amount
of soda the machine should dispense if the company wants to limit the percentage that need to be cleaned
because of spillage to 3%?
A) 12.1056 oz
B) 13.4944 oz
C) 12.1984 oz
D) 13.4016 oz
72) For a standard normal curve, find the z-score that separates the bottom 90% from the top 10%.
A) 1.28
B) 0.28
C) 2.81
D) 1.52
Determine the area under the standard normal curve that lies between:
73) z = 0.9 and z = 1.4
A) 0.1033
B) 0.1841
C) 0.8159
D) 0.9192
Provide an appropriate response.
74) The normal density curve is symmetric about
A) The horizontal axis
B) A point located one standard deviation from the mean
C) An inflection point
D) Its mean
A random variable X is normally distributed with µ = 60. Convert the value of X to a z-score, if the standard deviation is
as given.
75) X = 71; = 11
60
A)
B) 11
C) 71
D) 1
11
17
Provide an appropriate response.
76) According to the law of large numbers, as more observations are added to the sample, the difference between
the sample mean and the population mean
A) Is inversely affected by the data added
B) Remains about the same
C) Tends to become smaller
D) Tends to become larger
77) A simple random sample of size n = 1120 is obtained from a population whose size is N = 1,300,000 and whose
^
population proportion with a specified characteristic is p = 0.41. Describe the sampling distribution of p.
A) Approximately normal; µp = 0.41, p = 0.1364
B) Exactly normal; µp = 0.41, p = 0.1364
C) Approximately normal; µp = 0.41, p = 0.015
D) Exactly normal; µp = 0.41, p = 0.015
78) The National Association of Realtors estimates that 23% of all homes purchased in 2004 were considered
investment properties. If a sample of 800 homes sold in 2004 is obtained and it was noted that 248 homes were
to be used as investment property, would this be unusual? Answer Yes or No.
A) Yes
B) No
79) The ages of five randomly chosen cars in a parking garage are determined to be 7, 9, 3, 4, and 6 years old. If we
consider this sample of 5 in groups of 3, what is the probability of the population mean falling between 5.5 and
6.5 years?
A) 0.4
B) 0.6
C) 0.5
D) 0.55
80) Suppose a 98% confidence interval for µ turns out to be (1000, 2100). If this interval was based on a sample of
size n = 25, explain what assumptions are necessary for this interval to be valid.
A) The population must have an approximately normal distribution.
B) The sampling distribution of the sample mean must have a normal distribution.
C) The sampling distribution must be biased with 24 degrees of freedom.
D) The population of salaries must have an approximate t distribution.
18
81) A survey of 250 households showed 87 owned at least one snow blower. Find a point estimate for p, the
population proportion of households that own at least one snow blower.
A) 0.534
B) 0.348
C) 0.652
D) 0.258
82) A survey of 1010 college seniors working towards an undergraduate degree was conducted. Each student was
asked, "Are you planning or not planning to pursue a graduate degree?" Of the 1010 surveyed, 658 stated that
they were planning to pursue a graduate degree. Construct and interpret a 98% confidence interval for the
proportion of college seniors who are planning to pursue a graduate degree.
A) (0.616, 0.686); we are 98% confident that the proportion of college seniors who are planning to pursue a
graduate degree is between 0.616 and 0.686.
B) (0.612, 0.690); we are 98% confident that the proportion of college seniors who are planning to pursue a
graduate degree is between 0.612 and 0.690.
C) (0.621, 0.680); we are 98% confident that the proportion of college seniors who are planning to pursue a
graduate degree is between 0.621 and 0.680.
D) (0.620, 0.682); we are 98% confident that the proportion of college seniors who are planning to pursue a
graduate degree is between 0.620 and 0.682.
83) A confidence interval for p can be constructed using
^
A) p ± z /2
^
^
p(1 - p)
n
B) p ± z /2
p(1 - p)
n
C) p ± z
^
n
D) p ± z
n
84) A university dean is interested in determining the proportion of students who receive some sort of financial aid.
Rather than examine the records for all students, the dean randomly selects 200 students and finds that 118 of
them are receiving financial aid. If the dean wanted to estimate the proportion of all students receiving financial
aid to within 1% with 99% reliability, how many students would need to be sampled?
A) 3880
B) 6229
C) 16,040
D) 161
85) Find the critical t-value that corresponds to 99% confidence and n = 10.
A) 1.833
B) 2.821
C) 2.262
19
D) 3.250
86) Construct a 98% confidence interval for the population mean, µ. Assume the population has a normal
distribution. A study of 14 car owners showed that their average repair bill was $192 with a standard deviation
of $8.
A) ($115.40, $158.80)
B) ($222.30, $256.10)
C) ($328.30, $386.90)
D) ($186.30, $197.70)
87) A confidence interval for a parameter is
A) An interval of numbers combined with the likelihood the interval contains the unknown parameter.
B) A point estimate plus a margin of error.
C) A statement of believability of a statistical result.
D) An interval of probabilities concerning a parameter.
88) True or False: As the level of confidence increases the margin of error decreases.
A) False
B) True
89) The ______________ hypothesis contains the "=" sign.
A) explanatory
B) alternative
C) conditional
D) null
90) Find the critical value for a right-tailed test with
A) 1.28
B) 2.33
C) 1.645
D) 1.96
= 0.05.
91) Determine the standardized test statistic, z, to test the claim about the population proportion p 0.325 given
^
n = 42 and p = 0.247. Use
A) -1.54
= 0.05.
B) -2.575
C) -1.32
20
D) -1.08
92) You wish to test the claim that µ 1680 at a level of significance of
n = 35, x = 1650 and
A) -4.67
= 0.01 and are given sample statistics
= 82. Compute the value of the test statistic. Round your answer to two decimal places.
B) -5.18
C) -2.16
D) -3.82
93) Suppose you are using
= 0.01 to test the claim that µ = 1240 using a P-value. You are given the sample
statistics n = 35, x = 1210, and
A) 0.0308
= 82. Find the P-value.
B) 0.3169
C) 0.0154
D) 0.0077
94) True or False: Results that are practically significant will always be statistically significant.
A) False
B) True
95) The mean age of professors at a university is 53.1 years. If a hypothesis test is performed, how should you
interpret a decision that fails to reject the null hypothesis?
A) There is sufficient evidence to reject the claim µ = 53.1.
B) There is not sufficient evidence to reject the claim µ = 53.1.
C) There is not sufficient evidence to support the claim µ = 53.1.
D) There is sufficient evidence to support the claim µ = 53.1.
96) If the individuals selected for a sample have no influence upon which individuals are selected for a second
sample, then the samples are said to be
A) inconsistent
B) consistent
C) dependent
D) independent
21
97) True or False: When constructing a confidence interval for the difference of two population proportions, a
pooled estimate of p is not required.
A) True
B) False
98) Two surgical procedures are widely used to treat a certain type of cancer. To compare the success rates of the
two procedures, random samples of the two types of surgical patients were obtained and the numbers of
patients who showed no recurrence of the disease after a 1-year period were recorded. The data are shown in
the table. How large a sample would be necessary in order to estimate the difference in the true success rates to
within 0.10 with 95% reliability?
n
Number of Successes
Procedure A
100
86
Procedure B
100
79
A) n 1 = n 2 = 56
B) n 1 = n 2 = 192
C) n 1 = n 2 = 77
D) n 1 = n 2 = 110
99) Construct a 95% confidence interval for µ1 - µ2. Two samples are randomly selected from normal populations.
The sample statistics are given below.
n 1 = 10
n 2 = 12
x1 = 25
s1 = 1.5
A) (1.554, 3.651)
x2 = 23
s2 = 1.9
B) (0.360, 3.640)
C) (1.413, 3.124)
22
D) (1.335, 3.012)
100) Construct a 99% confidence interval for data sets A and B. Data sets A and B are dependent.
A
5.8
6.8
8.7
5.7
5.8
B
8.2
7.1
7.0
6.9
8.3
Assume that the paired data came from a population that is normally distributed.
A) (-25.123, 5.761)
B) (-4.502, 2.622)
C) (-15.123, 15.123)
D) (-21.342, 18.982)
101) The difference between the observed and predicted value of the response variable is a
A) residual
C) test statistic
102) Test the claim, at the
.
B) variance
D) standard error of the estimate
= 0.05 level of significance, that a linear relation exists between the two variables, for the
^
data below, given that y= -2.5x.
x -1 -2 -3 -4
y 2
6
7
10
A) There is sufficient evidence to support the claim of a linear relationship between the two variables.
B) There is not sufficient evidence to support the claim of a linear relationship between the two variables.
23