Z is a standard normal random variable. the p (1.41 < z < 2.85) equals

WEEK 3 QUIZ

Question 1

1.

A numerical description of the outcome of an experiment is called a

descriptive statistic

probability function

variance

random variable

Question 2
1.

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
1.

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
1.

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
1.

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
1.

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
1.

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
1.

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. x f(x) 0 0.80 1 0.15 2 0.04 3 0.01

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
1.

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
1.

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
1.

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
1.

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
1.

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
1.

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
1.

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