Assignment
QUESTION 1
A numerical description of the outcome of an experiment is called a
descriptive statistic
probability function
variance
random variable
QUESTION 2
A random variable that can assume only a finite number of values is referred to as a(n)
infinite sequence
finite sequence
discrete random variable
discrete probability function
QUESTION 3
A random variable that may take on any value in an interval or collection of intervals is known as a
continuous random variable
discrete random variable
continuous probability function
finite probability function
QUESTION 4
A description of the distribution of the values of a random variable and their associated probabilities is called a
probability distribution
random variance
random variable
expected value
QUESTION 5
The expected value for a binomial probability distribution is
E(x) = Pn(1 - n)
E(x) = P(1 - P)
E(x) = nP
E(x) = nP(1 - P)
QUESTION 6
The variance for the binomial probability distribution is
var(x) = P(1 - P)
var(x) = nP
var(x) = n(1 - P)
var(x) = nP(1 - P)
QUESTION 7
Which of the following is not a characteristic of an experiment where the binomial probability distribution is applicable?
the experiment has a sequence of n identical trials
exactly two outcomes are possible on each trial
the trials are dependent
the probabilities of the outcomes do not change from one trial to another
QUESTION 8
The number of electrical outages in a city varies from day to day. Assume that the number of electrical outages (x) in the city has the following probability distribution.
xf(x)
00.80
10.15
20.04
30.01
The mean and the standard deviation for the number of electrical outages (respectively) are
2.6 and 5.77
0.26 and 0.577
3 and 0.01
0 and 0.8
QUESTION 9
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 10
A normal distribution with a mean of 0 and a standard deviation of 1 is called
a probability density function
an ordinary normal curve
a standard normal distribution
none of these alternatives is correct
QUESTION 11
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 12
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 13
Z is a standard normal random variable. The P (1.41 ≤ Z ≤ 2.85) equals
0.4978
0.4207
0.9185
0.0771
QUESTION 14
X is a normally distributed random variable with a mean of 8 and a standard deviation of 4. The probability that X is between 1.48 and 15.56 is
0.0222
0.4190
0.5222
0.9190
QUESTION 15
Larger values of the standard deviation result in a normal curve that is
shifted to the right
shifted to the left
narrower and more peaked
wider and flatter