Question 1

In a standard normal distribution the value of z

Accepted Answer

A)  can be any value 
B)  cannot be negative 
C)  cannot be larger than 3.09 
D)  cannot be larger than 0.50

Question 2

Z is a standard normal random variable. What is the value of Z if the area between -Z and Z is 0.754?

Accepted Answer

A)  0.377 
B)  0.123 
C)  2.16 
D)  1.16

Question 3

For a standard normal distribution, determine the probability of obtaining a Z value of
a. greater than zero.
b. between -2.34 to -2.55
c. less than 1.86.
d. between -1.95 to 2.7.
e. between 1.5 to 2.75.

Accepted Answer

The answer of For a standard normal distribution, determine the...

Question 4

Exhibit 6-9
The average price of personal computers manufactured by MNM Company is $1,200 with a standard deviation of
$220. Furthermore, it is known that the computer prices manufactured by MNM are normally distributed.
-Refer to Exhibit 6-9. What is the minimum value of the middle 95% of computer prices?

Accepted Answer

A)  $1,768.80 
B)  $1,295.80 
C)  $2,400.00 
D)  $768.80

Question 5

The miles-per-gallon obtained by the 1995 model Z cars is normally distributed with a mean of 22 miles-per-gallon and a standard deviation of 5 miles-per-gallon.
a. What is the probability that a car will get between 13.35 and 35.1 miles-per-gallon?
b. What is the probability that a car will get more than 29.6 miles-per-gallon?
c. What is the probability that a car will get less than 21 miles-per-gallon?
d. What is the probability that a car will get exactly 22 miles-per-gallon?

Accepted Answer

The answer of The miles-per-gallon obtained by the 1995 model...

Question 6

Given that Z is a standard normal random variable, what is the value of Z if the area to the left of Z is 0.119?

Accepted Answer

A)  0.381 
B)  +1.18 
C)  -1.18 
D)  2.36

Question 7

Exhibit 6-2
The weight of football players is normally distributed with a mean of 200 pounds and a standard deviation of 25 pounds.
-Refer to Exhibit 6-2. What is the minimum weight of the middle 95% of the players?

Accepted Answer

A)  196 
B)  151 
C)  249 
D)  190

Question 8

In a normal distribution, it is known that 27.34% of all the items are included from 100 up to the mean, and another 45.99% of all the items are included from the mean up to 145. Determine the mean and the standard deviation of the distribution.

Accepted Answer

The answer of In a normal distribution, it is known...

Question 9

Which of the following is not a characteristic of the normal probability distribution?

Accepted Answer

A)  The mean, median, and the mode are equal 
B)  The mean of the distribution can be negative, zero, or positive 
C)  The distribution is symmetrical 
D)  The standard deviation must be 1

Question 10

The monthly earnings of computer systems analysts are normally distributed with a mean of $4,300. If only 1.07 percent of the systems analysts have a monthly income of more than $6,140, what is the value of the standard deviation of the monthly earnings of the computer systems analysts?

Accepted Answer

The answer of The monthly earnings of computer systems analysts...

Question 11

Exhibit 6-2
The weight of football players is normally distributed with a mean of 200 pounds and a standard deviation of 25 pounds.
-Refer to Exhibit 6-2. The probability of a player weighing less than 250 pounds is

Accepted Answer

A)  0.4772 
B)  0.9772 
C)  0.0528 
D)  0.5000

Question 12

Exhibit 6-8
The life expectancy of a particular brand of tire is normally distributed with a mean of 40,000 and a standard deviation of 5,000 miles.
-Refer to Exhibit 6-8. What is the probability that a randomly selected tire will have a life of exactly 47,500 miles?

Accepted Answer

A)  0.0000 
B)  0.9332 
C)  0.0668 
D)  0.4993

Question 13

The probability that a continuous random variable takes any specific value

Accepted Answer

A)  is equal to zero 
B)  is at least 0.5 
C)  depends on the probability density function 
D)  is very close to 1.0

Question 14

A standard normal distribution is a normal distribution

Accepted Answer

A)  with a mean of 1 and a standard deviation of 0 
B)  with a mean of 0 and a standard deviation of 1 
C)  with any mean and a standard deviation of 1 
D)  with any mean and any standard deviation

Question 15

In a standard normal distribution the probability of z being less than or equal zero is

Accepted Answer

A)  0.0000 
B)  much larger than 1 
C)  there is no answer to this question, since the value of the mean is not known 
D)  0.5000

Question 16

Given that Z is a standard normal random variable, what is the value of Z if the area to the right of Z is 0.9834?

Accepted Answer

A)  0.4834 
B)  -2.13 
C)  +2.13 
D)  zero

Question 17

Exhibit 6-3
Consider the continuous random variable X, which has a uniform distribution over the interval from 20 to 28.
-Refer to Exhibit 6-3. The probability that X will take on a value of at least 26 is

Accepted Answer

A)  0.000 
B)  0.125 
C)  0.250 
D)  1.000

Question 18

X is a normally distributed random variable with a mean of 12 and a standard deviation of 3. The probability that X equals 19.62 is

Accepted Answer

A)  0.000 
B)  0.0055 
C)  0.4945 
D)  0.9945

Question 19

X is a normally distributed random variable with a mean of 5 and a variance of 4. The probability that X is greater than 10.52 is

Accepted Answer

A)  0.0029 
B)  0.0838 
C)  0.4971 
D)  0.9971

Question 20

A major credit card company has determined that its customers charge an average of $280 per month on their accounts with a standard deviation of $20.
a. What percentage of the customers charges more than $275 per month?
b. What percentage of the customers charges less than $243 per month?
c. What percentage of the customers charges between $241 and $301.60 per month?

Accepted Answer

The answer of A major credit card company has determined...

Exam 6: Continuous Probability Distributions