Download ch6Apractest Using the following uniform density

ch6Apractest
Using the following uniform density curve, answer the question.
1) What is the probability that the random variable has a value greater than 2?
A) 0.625
B) 0.875
C) 0.700
D) 0.750
2) What is the probability that the random variable has a value between 4.1 and 7.4?
A) 0.6625
B) 0.5375
C) 0.4125
D) 0.2875
1)
2)
Assume that the weight loss for the first month of a diet program varies between 6 pounds and 12 pounds, and is spread
evenly over the range of possibilities, so that there is a uniform distribution. Find the probability of the given range of
pounds lost.
3) Less than 11 pounds
3)
5
5
1
1
A)
B)
C)
D)
7
6
6
3
4) Between 8.5 pounds and 10 pounds
1
1
A)
B)
4
2
3
C)
4
1
D)
3
4)
Find the area of the shaded region. The graph depicts the standard normal distribution with mean 0 and standard
deviation 1.
5)
5)
A) 0.8485
B) 0.1292
C) 0.8907
D) 0.8708
6)
6)
A) 0.2224
B) 0.2776
C) 0.7224
1
D) 0.2190
7)
7)
A) 0.8599
B) 0.7198
C) 0.2802
D) 0.1401
Find the indicated z score. The graph depicts the standard normal distribution with mean 0 and standard deviation 1.
8) Shaded area is 0.9599.
8)
A) -1.38
B) 1.03
C) 1.75
D) 1.82
9) Shaded area is 0.0901.
A) -1.39
9)
B) -1.45
C) -1.34
D) -1.26
10) Shaded area is 0.4483.
A) 0.13
10)
B) 0.6736
C) -0.13
D) 0.3264
C) 0.4920
D) 0.4910
12) The probability that z lies between -1.10 and -0.36
A) 0.4951
B) 0.2239
C) -0.2237
D) 0.2237
13) P(-0.73 < z < 2.27)
A) 0.7557
C) 0.4884
D) 0.2211
If z is a standard normal variable, find the probability.
11) The probability that z lies between -2.41 and 0
A) 0.0948
B) 0.5080
B) 1.54
2
11)
12)
13)
The Precision Scientific Instrument Company manufactures thermometers that are supposed to give readings of 0°C at
the freezing point of water. Tests on a large sample of these thermometers reveal that at the freezing point of water, some
give readings below 0°C (denoted by negative numbers) and some give readings above 0°C (denoted by positive
numbers). Assume that the mean reading is 0°C and the standard deviation of the readings is 1.00°C. Also assume that the
frequency distribution of errors closely resembles the normal distribution. A thermometer is randomly selected and
tested. Find the temperature reading corresponding to the given information.
14) If 7% of the thermometers are rejected because they have readings that are too high, but all other
14)
thermometers are acceptable, find the temperature that separates the rejected thermometers from
the others.
A) 1.48°
B) 1.45°
C) 1.39°
D) 1.26°
15) Find P40, the 40th percentile.
A) -0.57°
15)
B) -0.25°
C) 0.25°
D) 0.57°
16) A quality control analyst wants to examine thermometers that give readings in the bottom 4%. Find
the reading that separates the bottom 4% from the others.
A) -1.48°
B) -1.63°
C) -1.89°
D) -1.75°
16)
17) If 6.3% of the thermometers are rejected because they have readings that are too high and another
6.3% are rejected because they have readings that are too low, find the two readings that are cutoff
values separating the rejected thermometers from the others.
A) -1.45° , 1.45°
B) -1.53° , 1.53°
C) -1.46° , 1.46°
D) -1.39° , 1.39°
17)
Find the indicated value.
18) z0.005
A) 2.575
19) z0.02
A) 1.78
18)
B) 2.015
C) 2.535
D) 2.835
19)
B) 2.72
C) 1.99
D) 2.05
Provide an appropriate response.
20) Find the area of the shaded region. The graph depicts IQ scores of adults, and those scores are
normally distributed with a mean of 100 and a standard deviation of 15 (as on the Wechsler test).
A) 0.6293
B) 0.8051
C) 0.7486
3
D) 0.4400
20)
21) Find the area of the shaded region. The graph depicts IQ scores of adults, and those scores are
normally distributed with a mean of 100 and a standard deviation of 15 (as on the Wechsler test).
A) 0.7745
B) 0.7938
C) 0.7619
D) 0.7303
22) Find the indicated IQ score. The graph depicts IQ scores of adults, and those scores are normally
distributed with a mean of 100 and a standard deviation of 15 (as on the Wechsler test).
The shaded area under the curve is 0.10.
A) 100.5
B) 119.2
C) 108.1
21)
22)
D) 80.8
23) Assume that adults have IQ scores that are normally distributed with a mean of 100 and a standard
deviation of 15 (as on the Wechsler test). Find the probability that a randomly selected adult has an
IQ between 90 and 120 (somewhere in the range of normal to bright normal).
A) 0.6227
B) 0.6568
C) 0.6014
D) 0.6977
23)
24) Find the IQ score separating the top 16% from the others.
A) 107.3
B) 85.0
C) 99.5
24)
D) 114.9
Solve the problem. Round to the nearest tenth unless indicated otherwise.
25) In one region, the September energy consumption levels for single-family homes are found to be
normally distributed with a mean of 1050 kWh and a standard deviation of 218 kWh. Find P45,
which is the consumption level separating the bottom 45% from the top 55%.
A) 1087.8
B) 1148.1
C) 1078.3
25)
D) 1021.7
26) The amount of rainfall in January in a certain city is normally distributed with a mean of 4.3 inches
and a standard deviation of 0.3 inches. Find the value of the quartile Q1.
26)
27) Human body temperatures are normally distributed with a mean of 98.20°F and a standard
deviation of 0.62°F. Find the temperature that separates the top 7% from the bottom 93%. Round to
the nearest hundredth of a degree.
A) 98.78°F
B) 98.40°F
C) 99.12°F
D) 97.28°F
27)
A) 4.2
B) 1.1
C) 4.1
4
D) 4.5
28) The serum cholesterol levels for men in one age group are normally distributed with a mean of
178.3 and a standard deviation of 40.4. All units are in mg/100 mL. Find the two levels that separate
the top 9% and the bottom 9%.
A) 124.2 mg/100mL and 232.4 mg/100mL
B) 108.0 mg/100mL and 248.6 mg/100mL
C) 161.7 mg/100mL and 194.9 mg/100mL
D) 165.4 mg/100mL and 191.23 mg/100mL
Assume that X has a normal distribution, and find the indicated probability.
29) The mean is µ = 60.0 and the standard deviation is = 4.0.
Find the probability that X is less than 53.0.
A) 0.5589
B) 0.0401
C) 0.0802
30) The mean is µ= 15.2 and the standard deviation is
Find the probability that X is greater than 16.1.
A) 0.1357
B) 0.1587
29)
D) 0.9599
= 0.9.
C) 0.8413
31) The mean is µ = 15.2 and the standard deviation is = 0.9.
Find the probability that X is between 14.3 and 16.1.
A) 0.3413
B) 0.1587
C) 0.8413
32) The mean is µ = 137.0 and the standard deviation is = 5.3.
Find the probability that X is between 134.4 and 140.1.
A) 0.4069
B) 0.6242
C) 0.8138
28)
30)
D) 0.1550
31)
D) 0.6826
32)
D) 1.0311
Find the indicated probability.
33) The incomes of trainees at a local mill are normally distributed with a mean of $1100 and a
standard deviation of $150. What percentage of trainees earn less than $900 a month?
A) 40.82%
B) 35.31%
C) 9.18%
D) 90.82%
33)
34) The weekly salaries of teachers in one state are normally distributed with a mean of $490 and a
standard deviation of $45. What is the probability that a randomly selected teacher earns more than
$525 a week?
A) 0.2177
B) 0.1003
C) 0.7823
D) 0.2823
34)
35) Assume that the weights of quarters are normally distributed with a mean of 5.67 g and a standard
deviation 0.070 g. A vending machine will only accept coins weighing between 5.48 g and 5.82 g.
What percentage of legal quarters will be rejected?
A) 1.96%
B) 2.48%
C) 1.62%
D) 0.0196%
35)
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Answer Key
Testname: CH6APRAC
1) D
2) C
3) B
4) A
5) D
6) B
7) B
8) C
9) C
10) A
11) C
12) D
13) A
14) A
15) B
16) D
17) B
18) A
19) D
20) C
21) B
22) B
23) B
24) D
25) D
26) C
27) C
28) A
29) B
30) B
31) D
32) A
33) C
34) A
35) A
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