Chapter 6 Practice Complete Solution
Chapter 6 Practice
Question 1
If x is uniformly distributed over the interval 8 to 12, inclusively (8 ≤ x ≤ 12), then the probability, P(13 ≤ x ≤ 15), is ____________ .
0.250 |
|
0.500 |
|
0.375 |
|
0.000 |
|
1.000 |
Question 2
If x is uniformly distributed over the interval 8 to 12, inclusively (8 ≤ x ≤ 12), then P(x ≥ 10) is _____________ .
0.750 |
|
0.000 |
|
0.333 |
|
0.500 |
|
0.900 |
Question 3
If x, the time (in minutes) to complete an change job at certain auto service station, is uniformly distributed over the interval 20 to 30, inclusively (20 ≤ x ≤ 30), then the probability that an oil change job is completed in 21.75 to 24.25 minutes, inclusively, i.e., P(21.75 ≤ x ≤ 24.25) is ____________ .
0.250 |
|
0.333 |
|
0.375 |
|
0.000 |
|
1.000 |
Question 4
Let z be a normally distributed random variable with mean 0 and standard deviation 1. What is P(z < 1.3)?
0.4032 |
|
0.9032 |
|
0.0968 |
|
0.3485 |
|
0. 5485 |
Question 5
Let z be a normal random variable with mean 0 and standard deviation 1. What is P(z > -1.1)?
0.36432 |
|
0.8643 |
|
0.1357 |
|
-0.1357 |
|
-0.8643 |
Question 6
Within a range of z scores from -1 to +1, you can expect to find ______ percent of the values in a normal distribution.
95 |
|
99 |
|
68 |
|
34 |
|
100 |
Question 7
Sure Stone Tire Company has established that the useful life of a particular brand of its automobile tires is normally distributed with a mean of 40,000 miles and a standard deviation of 5000 miles. What is the probability that a randomly selected tire of this brand has a life of at least 50,000 miles?
0.0228 |
|
0.9772 |
|
0.5000 |
|
0.4772 |
|
1.0000 |
Question 8
The net profit of an investment is normally distributed with a mean of $10,000 and a standard deviation of $5,000. The probability that the investor's net gain will be at least $5,000 is ___________ .
0.1859 |
|
0.3413 |
|
0.8413 |
|
0.4967 |
|
0.5000 |
Question 9
The population of lengths of aluminum-coated steel sheets is normally distributed with a mean of 30.5 inches and a standard deviation of 0.2 inches.What is the probability that a sheet selected at random will be less than 31 inches long?
0.00 |
|
0.9938 |
|
.8289 |
|
.5987 |
Question 10
An apple juice producer buys all his apples from a conglomerate of apple growers in one northwest state. The amount of juice squeezed from each of these apples is approximately normally distributed with a mean of 2.25 ounces and a standard deviation of 0.15 ounce.
What is the probability that a randomly selected apple will contain between 2.00 and 3.00 ounces?
.0475 |
|
.4525 |
|
.9525 |
|
.9554 |
Question 11
An apple juice producer buys all his apples from a conglomerate of apple growers in one northwest state. The amount of juice squeezed from each of these apples is approximately normally distributed with a mean of 2.25 ounces and a standard deviation of 0.15 ounce.What is the probability that a randomly selected apple will contain between 2.00 and 2.15 ounces?
.4525 |
|
.2039 |
|
.2486 |
|
.7011 |
Question 12
A plant manager knows that the number of boxes of supplies received weekly is normally distributed with a mean of 200 and a standard deviation of 20. What percentage of the time will the number of boxes received weekly be between 180 and 210?
.6915 |
|
.1915 |
|
.5328 |
|
.1587 |
Question 13
The starting salaries of individuals with an MBA degree are normally distributed with a mean of $40,000 and a standard deviation of $5,000. What is the probability that a randomly selected individual with an MBA degree will get a starting salary of at least $30,000?
0.4772 |
|
0.9772 |
|
0.0228 |
|
0.5000 |
Question 14
The starting salaries of individuals with an MBA degree are normally distributed with a mean of $40,000 and a standard deviation of $5,000. What is the probability that a randomly selected individual with an MBA degree will get a starting salary of at least $47,500?
0.4332 |
|
0.9332 |
|
0.0668 |
|
0.5000 |
Question 15
The starting salaries of individuals with an MBA degree are normally distributed with a mean of $40,000 and a standard deviation of $5,000. What percentage of MBA's will have starting salaries of $34,000 to $46,000?
38.49% |
|
38.59% |
|
50% |
|
76.98% |
Question 16
A negative value of Z indicates that
the number of standard deviations of an observation is to the right of the mean |
|
the number of standard deviations of an observation is to the left of the mean |
|
a mistake has been made in computations, since Z cannot be negative |
|
the data has a negative mean |
Question 17
The center of a normal curve is
always equal to zero |
|
is the mean of the distribution |
|
cannot be negative |
|
is the standard deviation |
Question 18
Which of the following is not a characteristic of the normal probability distribution?
The mean, median, and the mode are equal |
|
The mean of the distribution can be negative, zero, or positive |
|
The distribution is symmetrical |
|
The standard deviation must be 1 |
Question 19
The weight of football players is normally distributed with a mean of 200 pounds and a standard deviation of 25 pounds. The probability of a player weighing more than 241.25 pounds is
0.4505 |
|
0.0495 |
|
0.9505 |
|
0.9010 |
Question 20
The weight of football players is normally distributed with a mean of 200 pounds and a standard deviation of 25 pounds. The probability of a player weighing less than 250 pounds is
0.4772 |
|
0.9772 |
|
0.0528 |
|
0.5000 |
Question 21
The weight of football players is normally distributed with a mean of 200 pounds and a standard deviation of 25 pounds. What percent of players weigh between 180 and 215 pounds?
28.81% |
|
6.24% |
|
22.57% |
|
51.38% |
Question 22
The weight of football players is normally distributed with a mean of 200 pounds and a standard deviation of 25 pounds.What is the minimum weight of the middle 95% of the players? (HINT: Apply the Empirical Rule to solve this question)
196 |
|
150 |
|
249 |
|
190 |
Chapter 6 Practice Complete Solution
Q1: If x is uniformly distributed over the interval 8 to 12, inclusively (8 ≤ x ≤ 12), then the probability, P(13 ≤ x ≤ 15), is zero Ans : zero (0.000) Q2: If x is uniformly distributed over the interval 8 to 1...
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