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Stats-2review
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MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
Provide an appropriate response.
1) Find the area of the indicated region under the standard normal curve.
A) 0.6562
B) 0.3438
C) 0.309
1)
D) 1.309
2) Find the area of the indicated region under the standard normal curve.
A) 0.9032
B) 0.9177
C) 0.0823
2)
D) 0.0968
3) Find the area of the indicated region under the standard normal curve.
A) 0.9032
B) 0.0823
C) 0.0968
3)
D) 0.4032
4) Find the area under the standard normal curve between z = 0 and z = 3.
A) 0.0010
B) 0.9987
C) 0.4641
D) 0.4987
5) Find the area under the standard normal curve between z = 1.5 and z = 2.5.
A) 0.9332
B) 0.9938
C) 0.0606
D) 0.9816
1
4)
5)
Find the probability of z occurring in the indicated region.
6)
-0.59
0
A) 0.1894
6)
z
B) 0.2776
C) 0.2224
D) 0.7224
7)
7)
0
A) 0.0401
1.75
z
B) 0.0668
C) 0.0228
2
D) 0.9599
8)
8)
0
A) 0.0668
1.50
z
B) 0.5668
C) 0.9332
D) 0.4332
Provide an appropriate response.
9) Use the standard normal distribution to find P(-2.25 < z < 1.25).
A) 0.0122
B) 0.8822
C) 0.4878
D) 0.8944
10) Use the standard normal distribution to find P(0 < z < 2.25).
A) 0.5122
B) 0.4878
C) 0.7888
D) 0.8817
9)
10)
Provide an appropriate response. Use the Standard Normal Table to find the probability.
11) IQ test scores are normally distributed with a mean of 100 and a standard deviation of 15. An
individual's IQ score is found to be 90. Find the z-score corresponding to this value.
A) -1.33
B) 1.33
C) -0.67
D) 0.67
11)
12) The lengths of pregnancies of humans are normally distributed with a mean of 268 days and a
standard deviation of 15 days. Find the probability of a pregnancy lasting more than 300 days.
A) 0.9834
B) 0.3189
C) 0.0166
D) 0.2375
12)
13) An airline knows from experience that the distribution of the number of suitcases that get lost each
week on a certain route is approximately normal with μ = 15.5 and σ = 3.6. What is the probability
that during a given week the airline will lose less than 20 suitcases?
A) 0.8944
B) 0.1056
C) 0.3944
D) 0.4040
13)
14) Assume that blood pressure readings are normally distributed with μ = 120 and σ = 8. A blood
pressure reading of 145 or more may require medical attention. What percent of people have a
blood pressure reading greater than 145?
A) 11.09%
B) 99.91%
C) 0.09%
D) 6.06%
14)
15) Assume that the heights of women are normally distributed with a mean of 63.6 inches and a
standard deviation of 2.5 inches. The cheerleaders for a local professional basketball team must be
between 65.5 and 68.0 inches. If a woman is randomly selected, what is the probability that her
height is between 65.5 and 68.0 inches?
A) 0.9608
B) 0.3112
C) 0.7881
D) 0.1844
15)
3
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
Provide an appropriate response.
16) Find the z-score that corresponds to the given area under the standard normal curve.
16)
17) Find the z-score that corresponds to the given area under the standard normal curve.
17)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
18) Find the z-score that has 84.85% of the distribution's area to its right.
A) -1.03
B) 0.39
C) -0.39
18)
D) 1.03
19) For the standard normal curve, find the z-score that corresponds to the 30th percentile.
A) -0.12
B) -0.53
C) -0.98
D) -0.47
19)
20) IQ test scores are normally distributed with a mean of 100 and a standard deviation of 15. Find the
x-score that corresponds to a z-score of 2.33.
A) 134.95
B) 142.35
C) 125.95
D) 139.55
20)
21) The scores on a mathematics exam have a mean of 77 and a standard deviation of 8. Find the
x-value that corresponds to the z-score 2.575.
A) 85.0
B) 79.6
C) 56.4
D) 97.6
21)
22) SAT scores have a mean of 1026 and a standard deviation of 209. ACT scores have a mean of 20.8
and a standard deviation of 4.8. A student takes both tests while a junior and scores 1130 on the
SAT and 25 on the ACT. Compare the scores.
A) You cannot determine which score is better from the given information.
B) A score of 25 on the ACT test was better.
C) The two scores are statistically the same.
D) A score of 1130 on the SAT test was better.
22)
23) In a certain normal distribution, find the standard deviation σ when μ = 50 and 10.56% of the area
lies to the right of 55.
A) 4
B) 3
C) 2
D) 5
23)
4
24) Assume that the heights of men are normally distributed with a mean of 68.4 inches and a standard
deviation of 2.8 inches. If 64 men are randomly selected, find the probability that they have a mean
height greater than 69.4 inches.
A) 0.8188
B) 9.9671
C) 0.9005
D) 0.0021
24)
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
25) Assume that the salaries of elementary school teachers in the United States are normally
distributed with a mean of $32,000 and a standard deviation of $3000. If 100 teachers are
randomly selected, find the probability that their mean salary is less than $32,500.
25)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
26) Assume that blood pressure readings are normally distributed with a mean of 120 and a standard
deviation of 8. If 100 people are randomly selected, find the probability that their mean blood
pressure will be greater than 122.
A) 0.8819
B) 0.8615
C) 0.0062
D) 0.9938
26)
Use the Central Limit Theorem to find the mean and standard error of the mean of the indicated sampling distribution.
27) The amounts of time employees of a telecommunications company have worked for the company
27)
are normally distributed with a mean of 5.1 years and a standard deviation of 2.0 years. Random
samples of size 18 are drawn from the population and the mean of each sample is determined.
A) 5.1 years, 0.11 years
B) 5.1 years, 0.47 years
C) 1.2 years, 2.0 years
D) 1.2 years, 0.47 years
28) The monthly rents for studio apartments in a certain city have a mean of $1040 and a standard
deviation of $170. Random samples of size 30 are drawn from the population and the mean of each
sample is determined.
A) $1040, $5.67
B) $1040, $31.04
C) $189.88, $31.04
D) $189.88, $170
Provide an appropriate response.
29) The weights of people in a certain population are normally distributed with a mean of 155 lb and a
standard deviation of 20 lb. Find the mean and standard error of the mean for this sampling
distribution when using random samples of size 3.
A) 155, 6.67
B) 155, 11.55
C) 155, 3
D) 155, 20
28)
29)
30) Ten percent of the population is left-handed. A class of 2350 students is selected. Convert the
binomial probability P(x ≥ 17) to a normal probability by using the correction for continuity.
A) P(x > 17.5)
B) P(x < 16.5)
C) P(x ≥ 17.5)
D) P(x ≥ 16.5)
30)
31) Ten percent of the population is left-handed. A class of 8600 students is selected. Convert the
binomial probability P(x > 10) to a normal probability by using the correction for continuity.
A) P(x ≤ 10.5)
B) P(x ≥ 9.5)
C) P(x < 9.5)
D) P(x > 10.5)
31)
32) A telemarketer found that there was a 1% chance of a sale from his phone solicitations. Find the
probability of getting 5 or more sales for 1000 telephone calls.
A) 0.8810
B) 0.0871
C) 0.9599
D) 0.0401
32)
33) An airline 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) 0.7967
C) 0.2451
D) 0.7549
33)
5
34) A student answers all 48 questions on a multiple-choice test by guessing. Each question has four
possible answers, only one of which is correct. Find the probability that the student gets exactly 15
correct answers. Use the normal distribution to approximate the binomial distribution.
A) 0.0823
B) 0.7967
C) 0.8577
D) 0.0606
34)
35) A random sample of 40 students has a mean annual earnings of $3120 and a standard deviation of
$677. Find the margin of error if c = 0.95.
A) $77
B) $210
C) $2891
D) $7
35)
36) In order to set rates, an insurance company is trying to estimate the number of sick days that full
time workers at an auto repair shop take per year. A previous study indicated that the standard
deviation was 2.8 days. How large a sample must be selected if the company wants to be 95%
confident that the true mean differs from the sample mean by no more than 1 day?
A) 1024
B) 31
C) 141
D) 512
36)
37) Find the critical value, tc, for c = 0.95 and n = 16.
37)
A) 2.120
B) 2.602
C) 2.947
D) 2.131
38) Construct a 95% confidence interval for the population mean, μ. Assume the population has a
normal distribution. A sample of 20 college students had mean annual earnings of $3120 with a
standard deviation of $677.
A) ($2803, $3437)
B) ($2657, $2891)
C) ($1324, $1567)
D) ($2135, $2567)
38)
39) Construct a 90% confidence interval for the population mean, μ. Assume the population has a
normal distribution. In a recent study of 22 eighth graders, the mean number of hours per week
that they watched television was 19.6 with a standard deviation of 5.8 hours.
A) (17.47, 21.73)
B) (5.87, 7.98)
C) (18.63, 20.89)
D) (19.62, 23.12)
39)
40) When 435 college students were surveyed,120 said they own their car. Find a point estimate for p,
the population proportion of students who own their cars.
A) 0.276
B) 0.724
C) 0.216
D) 0.381
40)
41) A survey of 2450 golfers showed that 281 of them are left-handed. Construct a 98% confidence
interval for the proportion of golfers that are left-handed.
A) (0.369, 0.451)
B) (0.683, 0.712)
C) (0.100, 0.130)
D) (0.203, 0.293)
41)
42) A manufacturer of golf equipment wishes to estimate the number of left-handed golfers. How
large a sample is needed in order to be 98% confident that the sample proportion will not differ
from the true proportion by more than 2%? A previous study indicates that the proportion of
left-handed golfers is 8%.
A) 707
B) 999
C) 1086
D) 17
42)
43) A researcher wishes to estimate the number of households with two cars. How large a sample is
needed in order to be 98% confident that the sample proportion will not differ from the true
proportion by more than 5%? A previous study indicates that the proportion of households with
two cars is 19%.
A) 413
B) 237
C) 335
D) 8
43)
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Answer Key
Testname: STATS-2REVIEW
1) A
2) A
3) C
4) D
5) C
6) B
7) A
8) D
9) B
10) B
11) C
12) C
13) A
14) C
15) D
16) z = -0.58
17) z = 3.07
18) A
19) B
20) A
21) D
22) B
23) A
24) D
25) 0.9525
26) C
27) B
28) B
29) B
30) D
31) D
32) C
33) C
34) A
35) B
36) B
37) D
38) A
39) A
40) A
41) C
42) B
43) C
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