Download ProbStat PRACTICE Test 6.1-6.2.tst

ProbStat PRACTICE TEST 6.1-6.2
Name___________________________________
1) Find the area under the standard normal curve to the left of z = 2.6.
1)
2) Find the area under the standard normal curve to the right of z = -2.2.
2)
3) Find the area under the standard normal curve that lies between z = -2.8 and
z = -2.2.
3)
4) The average height of flowering cherry trees in a certain nursery is 10.5 feet. If
the heights are normally distributed with a standard deviation of 1.5 feet, find
the probability that a tree is less than 12.5 feet tall.
4)
5) A normal population has a mean µ = 24 and standard deviation σ = 5. What is
the probability that a randomly chosen value will be greater than 26?
5)
6) The average gas mileage of a certain model car is 26.0 miles per gallon. If the
gas mileages are normally distributed with a standard deviation of 0.15 miles
per gallon, find the probability that a car has a gas mileage of between 25.8 and
26.2 miles per gallon.
6)
7) Find the probability P(z < 0.32) using the standard normal distribution.
7)
8) Find the probability P(z > -0.74) using the standard normal distribution.
8)
9) Find the probability P(-0.94 < z < 1.21) using the standard normal distribution.
9)
10) Find the z-score for which the area to the left is 0.14.
10)
11) Find the z-score for which the area to the right is 0.77.
11)
12) Find the z-scores that bound the middle 92% of the area under the standard
normal curve.
12)
13) X is a normally distributed random variable with a standard deviation of 3.00.
Find the mean of X when 64.8% of the area lies to the left of 9.14.
13)
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14) X is a normally distributed random variable with a mean of 5 and a standard
deviation of 2.0. Find the value of X for which 70.54% of the area under the
distribution curve lies to the right of it.
14)
15) X is a normally distributed random variable with a mean of 11.0. If 59.10% of
the data lies to the right of 10.43 find the standard deviation.
15)
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Answer Key
Testname: PROBSTAT PRACTICE TEST 6.1-6.2
1) 0.9953
2) 0.9861
3) 0.0113
4) 0.91
5) 0.3446
6) 0.816
7) 0.6255
8) 0.7704
9) 0.7133
10) -1.08
11) -0.74
12) -1.75, 1.75
13) 8.0
14) 3.92
15) 2.5
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