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If each of a set of raw scores is transformed into a Z-score, the new distributi

ID: 2932475 • Letter: I

Question

If each of a set of raw scores is transformed into a Z-score, the new distribution will have a standard deviation equal to

the standard deviation of the original distribution

the mean of the original distribution

zero

one

3.5 points   

QUESTION 6

On the average, 1,234 students check in at the student recreation center every day. Define the random variable X to be the number of students checking in in any day. What is the appropriate probability distribution for X?

binomial probability distribution

uniform probability distribution

hypergeometric probability distribution

Poisson probability distribution

3.5 points   

QUESTION 7

The expected value of a discrete random variable

is a measure of central location of the random variable

is always equal to the median value of the random variable

is a description of the distribution of the values of a random variable and their associated probabilities

None of these alternatives is correct.

3.5 points   

QUESTION 8

Consider a Poisson probability distribution with µ = 0.6. The variance of this distribution is

0.36

0.40

0.60

1.00

3.5 points   

QUESTION 9

A sample of 100 people was asked how many cups of coffee they drink in the morning. You are given the following sample information:

Cups of Coffee

Frequency

0

30

1

45

2

20

3

5

100

The expected number of cups of coffee is

1.0

1.5

2.0

2.5

3.5 points   

QUESTION 10

In a standard normal distribution, the range of values of z is from

0 to 1

-1 to 1

-3.09 to 3.09

3.5 points   

QUESTION 11

Consider a probability density function for a uniform distribution ranging between 3 and 7. What is P(2 x 4)?

0.25

0.50

0.75

1.00

3.5 points   

QUESTION 12

The student body of a large university consists of 43% female students. A random sample of 4 students is selected. What is the probability that among the students in the sample exactly two are female?

0.3560

0.3604

0.3643

None of these alternatives is correct.

3.5 points   

QUESTION 13

The number of cars that enter the drive-thru windows at the restaurant during one hour is an example of

a continuous random variable

a discrete random variable

either a continuous or a discrete random variable, depending on the number of the vehicles

either a continuous or a discrete random variable, depending on the color of the vehicles

3.5 points   

QUESTION 14

For a standard normal distribution, a zero value of z indicates that

the sample mean is larger than the population mean

the actual data value is equal to the sample mean

the sample mean is smaller than the population mean

a mistake has been made in computations, since Z cannot be zero

3.5 points   

QUESTION 15

When dealing with the number of occurrences of an event over a specified interval of time or space, the appropriate probability distribution is a

hypergeometric probability distribution

Poisson probability distribution

normal probability distribution

binomial probability distribution

3.5 points   

QUESTION 16

Z-scores provide information about the location of raw scores

below the mean in units of the range of the distribution

above the mean in units of the standard deviation of the distribution

above and below the mean in units of the range of the distribution

above and below the mean in standard deviation units from the mean

3.5 points   

QUESTION 17

The time it takes a mechanic to change the oil in a car is exponentially distributed with a mean of 3 minutes. What is the probability that it will take a mechanic less than 3 minutes to change the oil?

0.4512

0.5000

0.6321

0.6988

3.5 points   

QUESTION 18

What area under the standard normal curve falls outside the Z values -2.3 and 2.3?

0.0107

0.0214

0.9786

0.9893

3.5 points   

QUESTION 19

A uniform probability distribution is a continuous probability distribution where the probability that the random variable assumes a value in any interval of equal length is

the same for each interval

different for each interval

equal to 100

at least one

3.5 points   

QUESTION 20

X is a random variable with the probability function: f(X) = X/12 for X = 3, 4 or 5

The expected value of X is

2.33

4

4.17

12

3.5 points   

QUESTION 21

If a normal distribution has mean 100 and standard deviation 10, find K so that the probability that a sample value is less than K is .975. (Choose the closest.)

114

116

118

120

3.5 points   

QUESTION 22

Which of the following statements about a discrete random variable and its probability distribution is false?

Values of the discrete random variable can be either a finite number of values or an infinite sequence of values.

Negative values of f(x) are not allowed even though f(x) = 1.

Values of f(x) can be anything (greater than or less than or equal to zero).

All of these alternatives are true statements about a discrete random variable.

3.5 points   

QUESTION 23

For a continuous random variable x, the height of the function at x is

0.50, since it is the middle value

a value less than zero

named the probability density function f(x)

the probability at a given value of x

3.5 points   

QUESTION 24

For the standard normal probability distribution, the area to the left of the mean is

equal to the area to the right of the mean

0.5

1.0

Both a. and b. are correct.

3.5 points   

QUESTION 25

In a binomial experiment the probability of success is 0.6. What is the probability of three successes in five trials?

0.0019

0.0299

0.2304

0.3456

3.5 points   

QUESTION 26

A continuous probability distribution that is useful in describing the time, or space, between occurrences of an event is a(n)

uniform probability distribution

Poisson probability distribution

exponential probability distribution

normal probability distribution

3.5 points   

QUESTION 27

Which of the following is not a property of a binomial experiment?

The probability of a failure does not change from one trial to the next.

Two outcomes referred to as a success or a failure are possible on each trial.

The experiment consists of a sequence of n identical trials.

The trials are dependent.

3.5 points   

QUESTION 28

Compute the hypergeometric probabilities for the value of n = 4 and x = 2. Assume N = 8 and r = 5.

0.0000

0.1786

0.4286

0.8571

3.5 points   

QUESTION 29

The distribution of lifetimes for a certain type of light bulb is normally distributed with a mean of 500 hours and a standard deviation of 50 hours. Find the 33rd percentile of the distribution of lifetimes.

456

478

500

956

3.5 points   

QUESTION 30

The height of an object is an example of

a continuous random variable

a discrete random variable

either a continuous or a discrete random variable, depending on the height of the object

either a continuous or a discrete random variable, depending on the units of measurement

a.

the standard deviation of the original distribution

b.

the mean of the original distribution

c.

zero

d.

one

Explanation / Answer

Q 1 ) If each of a set of raw scores is transformed into a Z-score, the new distribution will have a standard deviation equal to

Answer: Option d: One

Q 6 ) On the average, 1,234 students check in at the student recreation center every day. Define the random variable X to be the number of students checking in in any day. What is the appropriate probability distribution for X?

Answer: Poisson probabilty distribution

Q7 ) The expected value of a discrete random variable

is a measure of central location of the random variable

Q8 ) Consider a Poisson probability distribution with µ = 0.6. The variance of this distribution is

Answer: 0.6, because mean and sd is equal for Poisson distribution

Answer: a.

is a measure of central location of the random variable

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