Question 1
Suppose you are working with a data set that is normally distributed with a mean of 400
and a standard deviation of 20. Determine the value of x such that 5% of the values are less than x.
Select one:
a. 396
b. 432.9
c. 404
d. 367.1
Question 2
The uniform distribution is also known as the __________.
Select one:
a. rectangular distribution
b. gamma distribution
c. beta distribution
d. Erlang distribution
Question 3
Completion time (from start to finish) of a building remodelling project is normally
distributed with a mean of 200 work-days and a standard deviation of 10 work-days. The
probability that the project will be completed within 215 work-days is _____.
Select one:
a. 0.9332
b. 0.4332
c. 0.5000
d. 0.0668
Question 4
The EPA has reported that the average fuel cost for a particular type of car is $800 with a standard deviation of $80. Fuel cost is assumed to be normally distributed. If one of these cars is randomly selected, what is the probability that the fuel cost for this car exceeds $760?
Select one:
a. 0.1915
b. 0.8085
c. 0.3085
d. 0.6915
Question 5
Within a range of z scores from -2 to +2, you can expect to find _______ per cent of the
values in a normal distribution.
Select one:
a. 34
b. 68
c. 99
d. 95
Question 6
For any normal distribution, any value less than the mean would have a _______.
Select one:
a. negative probability of occurring
b. positive z-score
c. negative z-score
d. negative variance
Question 7
The Environment Protection Authority has reported that the average fuel cost for a particular type of car is $800 with a standard deviation of $80. Fuel cost is assumed to be normally distributed. If one of these cars is randomly selected, what is the probability that the fuel cost for this car exceeds $760?
Select one:
a. 0.8085
b. 0.1915
c. 0.6915
d. 0.3085
Question 8
A z-score is the number of __________ that a value is from the mean.
Select one:
a. standard deviations
b. units
c. miles
d. variances
Question 9
Let Z be a normal random variable with mean 0 and standard deviation 1. Use the normal
tables to find P(Z > -1.1).
Select one:
a. 0.3643
b. 0.1357
c. 0.8643
d. -0.1357
Question 10
Which of the following is NOT a continuous distribution?
Select one:
a. normal distribution
b. exponential distribution
c. binomial distribution
d. uniform distribution
Question 11
The normal distribution is also referred to as _______.
Select one:
a. the Poisson distribution
b. the Gaussian distribution
c. the de Moivre distribution
d. the exponential distribution
Question 12
The weights of aluminium castings produced by a process are normally distributed with µ = 2 kg and σ = 0.10 kg. Design specifications require the castings to weigh between 1.836 and 2.164 kg, inclusively. The probability that a casting produced by this process will conform to design specifications is _________.
Select one:
a. 0.9974
b. 0.8990
c. 0.9500
d. 0.4495
Question 13
Let X be a normal random variable with mean 20 and standard deviation 4. Find P(X < 17).
Select one:
a. 0.2266
b. 0.7734
c. 0.2734
d. –0.2734
Question 14
Suppose you are working with a data set that is normally distributed with a mean of 400
and a standard deviation of 20. Determine the value of x such that 60% of the values are
greater than x.
Select one:
a. 404.5
b. 405.0
c. 395.5
d. 395.0
Question 15
The Environmental Protection Authority has reported that the average fuel cost for a particular type of car is $800 with a standard deviation of $80. Fuel cost is assumed to be normally distributed. If a car is randomly selected, what is the probability that fuel cost would be between $700 and $900?
Select one:
a. 0.3944
b. 0.7888
c. 0.1056
d. 0.8944
Question 16
The distribution in the following graph is a ________ distribution.
Select one:
a. normal
b. gamma
c. uniform
d. exponential
Question 17
The EPA has reported that the average fuel cost for a particular type of car is $800 with a standard deviation of $80. Fuel cost is assumed to be normally distributed. If a car is randomly selected, what is the probability that fuel cost would be between $700 and $900?
Select one:
a. 0.1056
b. 0.3944
c. 0.7888
d. 0.8944
Question 18
Suppose X is a normal random variable with mean 60 and standard deviation 2. A z-score
was calculated for a number, and the z-score is 3.4. What is x?
Select one:
a. 56.6
b. 63.4
c. 66.8
d. 53.2
Question 19
Let Z be a normal random variable with mean 0 and standard deviation 1. Use the normal tables to find P(Z > 2.4).
Select one:
a. 0.4918
b. 0.9918
c. 0.0082
d. 0.4793
Question 20
Let Z be a normal random variable with mean 0 and standard deviation 1. Use the normal
tables to find P(Z < 1.3).
Select one:
a. 0.0968
b. 0.3485
c. 0.4032
d. 0.9032
