Question 1

For a continuous random variable x, the probability density function f(x) represents the

Accepted Answer

A)  probability at a given value of x. 
B)  area under the curve at x. 
C)  area under the curve to the right of x. 
D)  height of the function at x. 
A)  probability at a given value of x. 
B)  area under the curve at x. 
C)  area under the curve to the right of x. 
D)  height of the function at x.

Question 2

The travel time for a college student traveling between her home and her college is uniformly distributed between 40 and 90 minutes. The probability that her trip will take exactly 50 minutes is

Accepted Answer

A)  zero. 
B)  0.02. 
C)  0.06. 
D)  0.20. 
A)  zero. 
B)  0.02. 
C)  0.06. 
D)  0.20.

Question 3

The standard deviation of a standard normal distribution

Accepted Answer

A)  is always equal to zero. 
B)  is always equal to one. 
C)  can be any positive value. 
D)  can be any value. 
A)  is always equal to zero. 
B)  is always equal to one. 
C)  can be any positive value. 
D)  can be any value.

Question 4

Given that z is a standard normal random variable, what is the value of z if the area to the right of z is 0.5?

Accepted Answer

A)  0.0000 
B)  1.0000 
C)  0.1915 
D)  0.3413 
A)  0.0000 
B)  1.0000 
C)  0.1915 
D)  0.3413

Question 5

Given that z is a standard normal random variable, what is the value of z if the area between -z and z is 0.9812?

Accepted Answer

A)    2.35 
B)    2.07 
C)    0.25 
D)    1.96 
A)    2.35 
B)    2.07 
C)    0.25 
D)    1.96

Question 6

Whenever the probability is proportional to the length of the interval in which the random variable can assume a value, the random variable is _____ distributed.

Accepted Answer

A)  uniformly 
B)  normally 
C)  Poisson 
D)  exponentially 
A)  uniformly 
B)  normally 
C)  Poisson 
D)  exponentially

Question 7

For any continuous random variable, the probability that the random variable takes on exactly a specific value is

Accepted Answer

A)  1.00. 
B)  0.50. 
C)  any value between 0 to 1. 
D)  0. 
A)  1.00. 
B)  0.50. 
C)  any value between 0 to 1. 
D)  0.

Question 8

What is the mean of x, given the function below? f(x) = (1/10) e-x/10 x   0

Accepted Answer

A)  0.10 
B)  10 
C)  100 
D)  1,000 
A)  0.10 
B)  10 
C)  100 
D)  1,000

Question 9

The travel time for a college student traveling between her home and her college is uniformly distributed between 40 and 90 minutes. The probability that her trip will take longer than 80 minutes is

Accepted Answer

A)  1.00. 
B)  0.40. 
C)  0.20. 
D)  0.80. 
A)  1.00. 
B)  0.40. 
C)  0.20. 
D)  0.80.

Question 10

Given that z is a standard normal random variable, what is the probability that -2.51   z   -1.53?

Accepted Answer

A)  0.4950 
B)  0.4370 
C)  0.0570 
D)  0.9310 
A)  0.4950 
B)  0.4370 
C)  0.0570 
D)  0.9310

Question 11

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. What is the probability that a randomly selected tire will have a life of exactly 42,500 miles?

Accepted Answer

A)  0.0000 
B)  1.0000 
C)  0.5000 
D)  0.9500 
A)  0.0000 
B)  1.0000 
C)  0.5000 
D)  0.9500

Question 12

z is a standard normal random variable. The P(-1.96   z   1.4) equals

Accepted Answer

A)  0.9442. 
B)  0.0558. 
C)  0.8942. 
D)  0.1058. 
A)  0.9442. 
B)  0.0558. 
C)  0.8942. 
D)  0.1058.

Question 13

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

Accepted Answer

A)  different for each interval. 
B)  the same for each interval. 
C)  at least one. 
D)  zero. 
A)  different for each interval. 
B)  the same for each interval. 
C)  at least one. 
D)  zero.

Question 14

The mean of a standard normal probability distribution

Accepted Answer

A)  is always equal to zero. 
B)  can be any value as long as it is positive. 
C)  can be any value. 
D)  is always greater than zero. 
A)  is always equal to zero. 
B)  can be any value as long as it is positive. 
C)  can be any value. 
D)  is always greater than zero.

Question 15

A continuous random variable may assume

Accepted Answer

A)  all values in an interval or collection of intervals. 
B)  only integer values in an interval or collection of intervals. 
C)  only fractional values in an interval or collection of intervals. 
D)  all the positive integer values in an interval. 
A)  all values in an interval or collection of intervals. 
B)  only integer values in an interval or collection of intervals. 
C)  only fractional values in an interval or collection of intervals. 
D)  all the positive integer values in an interval.

Question 16

If the mean of a normal distribution is negative,

Accepted Answer

A)  the standard deviation must also be negative. 
B)  the variance must also be negative. 
C)  a mistake has been made in the computations, because the mean of a normal distribution cannot be negative. 
D)  none of these alternatives is correct. 
A)  the standard deviation must also be negative. 
B)  the variance must also be negative. 
C)  a mistake has been made in the computations, because the mean of a normal distribution cannot be negative. 
D)  none of these alternatives is correct.

Question 17

The weight of football players is normally distributed with a mean of 200 pounds and a standard deviation of 25 pounds. The probability of a player weighing less than 240 pounds is

Accepted Answer

A)  0.0548. 
B)  0.9452. 
C)  0.9956. 
D)  0.0044. 
A)  0.0548. 
B)  0.9452. 
C)  0.9956. 
D)  0.0044.

Question 18

For a standard normal distribution, the probability of obtaining a z value of less than 1.65 is

Accepted Answer

A)  0.8977. 
B)  0.0123. 
C)  0.0495. 
D)  0.9505. 
A)  0.8977. 
B)  0.0123. 
C)  0.0495. 
D)  0.9505.

Question 19

The time it takes to travel from home to the office is normally distributed with μ = 25 minutes and σ = 5 minutes. What is the probability the trip takes between 20 and 30 minutes?​

Accepted Answer

A)  ​.3413 
B)  ​.4206 
C)  ​.6826 
D)  ​.8413 
A)  ​.3413 
B)  ​.4206 
C)  ​.6826 
D)  ​.8413

Question 20

The time it takes to travel from home to the office is normally distributed with μ = 25 minutes and σ = 5 minutes. What is the probability the trip takes more than 32 minutes?

Accepted Answer

A)  .9701 
B)  .1995 
C)  .9192 
D)  .0808 
A)  .9701 
B)  .1995 
C)  .9192 
D)  .0808

Exam 6: Continuous Probability Distributions

For a continuous random variable x, the probability density function f(x) represents the

The travel time for a college student traveling between her home and her college is uniformly distributed between 40 and 90 minutes. The probability that her trip will take exactly 50 minutes is

The standard deviation of a standard normal distribution

Given that z is a standard normal random variable, what is the value of z if the area to the right of z is 0.5?

Given that z is a standard normal random variable, what is the value of z if the area between -z and z is 0.9812?

Whenever the probability is proportional to the length of the interval in which the random variable can assume a value, the random variable is _____ distributed.

For any continuous random variable, the probability that the random variable takes on exactly a specific value is

What is the mean of x, given the function below? f(x) = (1/10) e-x/10 x 0

The travel time for a college student traveling between her home and her college is uniformly distributed between 40 and 90 minutes. The probability that her trip will take longer than 80 minutes is

Given that z is a standard normal random variable, what is the probability that -2.51 z -1.53?

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. What is the probability that a randomly selected tire will have a life of exactly 42,500 miles?

z is a standard normal random variable. The P(-1.96 z 1.4) equals

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 mean of a standard normal probability distribution

A continuous random variable may assume

If the mean of a normal distribution is negative,

The weight of football players is normally distributed with a mean of 200 pounds and a standard deviation of 25 pounds. The probability of a player weighing less than 240 pounds is

For a standard normal distribution, the probability of obtaining a z value of less than 1.65 is

The time it takes to travel from home to the office is normally distributed with μ = 25 minutes and σ = 5 minutes. What is the probability the trip takes between 20 and 30 minutes?​

The time it takes to travel from home to the office is normally distributed with μ = 25 minutes and σ = 5 minutes. What is the probability the trip takes more than 32 minutes?

Data and Statistics

Descriptive Statistics: Tabular and Graphical Displays

Descriptive Statistics: Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Sampling and Sampling Distributions

Interval Estimation

Hypothesis Tests

Inference About Means and Proportions With Two Populations

Inferences About Population Variances

Comparing Multiple Proportions, Tests of Independence and Goodness of Fit

Experimental Design and Analysis of Variance

Simple Linear Regression

Multiple Regression

Regression Analysis: Model Building

Time Series Analysis and Forecasting

Nonparametric Methods

Decision Analysis

Index Numbers

Statistical Methods for Quality Control

Sample Survey

Filters

What is the mean of x, given the function below? f(x) = (1/10) e-x^/10 x 0

The time it takes to travel from home to the office is normally distributed with μ = 25 minutes and σ = 5 minutes. What is the probability the trip takes between 20 and 30 minutes?