Question 1

For a standardized normal distribution,calculate P(z < 1.5).

Accepted Answer

A) 0.9332 
B) 0.0668 
C) 0.333 
D) 0.667 
A) 0.9332 
B) 0.0668 
C) 0.333 
D) 0.667

Question 2

In a standard normal distribution,the probability that z is greater than 0 is:

Accepted Answer

A) 0.5 
B) equal to 1 
C) at least 0.5 
D) 1.96 
A) 0.5 
B) equal to 1 
C) at least 0.5 
D) 1.96

Question 3

A professor noted that the grades of his students were normally distributed with a mean of 75.07 and a standard deviation of 11.65.If only 10 percent of the students received grades of A,what is the minimum score needed to receive an A?

Accepted Answer

A) 80.00 
B) 85.00 
C) 90.00 
D) 95.00 
A) 80.00 
B) 85.00 
C) 90.00 
D) 95.00

Question 4

Employees at a large computer company earn sick leave in one-minute increments depending on how many hours per month they work.They can then use the sick leave time any time throughout the year.Any unused time goes into a sick bank account that they or other employees can use in the case of emergencies.The human resources department has determined that the amount of unused sick time for individual employees is uniformly distributed between 0 and 480 minutes.Based on this information,what is the probability that three randomly chosen employees have over 400 unused sick minutes at the end of the year?

Accepted Answer

A) 0.1667 
B) 0.0046 
C) 0.5001 
D) 0.0300 
A) 0.1667 
B) 0.0046 
C) 0.5001 
D) 0.0300

Question 5

A random variable is normally distributed with a mean of 25 and a standard deviation of 5.If an observation is randomly selected from the distribution,determine two values of which the smallest has 25% of the values below it and the largest has 25% of the values above it.

Accepted Answer

A) 18.85 and 27.94 
B) 19.31 and 21.12 
C) 16.23 and 18.82 
D) 21.65 and 28.35 
A) 18.85 and 27.94 
B) 19.31 and 21.12 
C) 16.23 and 18.82 
D) 21.65 and 28.35

Question 6

Consider a random variable,z,that has a standardized normal distribution.Determine (-2 ≤ z ≤ 3).

Accepted Answer

A) 0.12414 
B) 0.97587 
C) 0.47722 
D) 0.49865 
A) 0.12414 
B) 0.97587 
C) 0.47722 
D) 0.49865

Question 7

The manager at a local movie theater has collected data for a long period of time and has concluded that the revenue from concession sales during the first show each evening is normally distributed with a mean equal to $336.25 and a standard deviation equal to $80.Based on this information,what are the chances that the revenue on the first show will be between $300 and $500?

Accepted Answer

A) About 0.3062 
B) Approximately 0.6534 
C) 0.1736 
D) Approximately 0.4798 
A) About 0.3062 
B) Approximately 0.6534 
C) 0.1736 
D) Approximately 0.4798

Question 8

An electronics repair shop has determined that the time between failures for a particular electronic component part is exponentially distributed with a mean time between failures of 200 hours.Based on this information,the probability that a part will fail in the first 20 hours is approximately 0.095.

Accepted Answer

A) True 
 B)False

Question 9

Which of the following probability distributions can be used to describe the distribution for a continuous random variable?

Accepted Answer

A) Normal distribution 
B) Binomial distribution 
C) Poisson distribution 
D) Hypergeometric 
A) Normal distribution 
B) Binomial distribution 
C) Poisson distribution 
D) Hypergeometric

Question 10

The manager of a computer help desk operation has collected enough data to conclude that the distribution of time per call is normally distributed with a mean equal to 8.21 minutes and a standard deviation of 2.14 minutes.What is the probability that three randomly monitored calls will each be completed in 4 minutes or less?

Accepted Answer

A) 0.4756 
B) Approximately 0.1076 
C) About 0.00001 
D) Can't be determined without more information. 
A) 0.4756 
B) Approximately 0.1076 
C) About 0.00001 
D) Can't be determined without more information.

Question 11

It has been determined the weight of bricks made by the Dillenger Stone Company is uniformly distributed between 1 and 1.5 pounds.Based on this information,the probability that two randomly selected bricks will each weigh more than 1.3 pounds is 0.16.

Accepted Answer

A) True 
 B)False

Question 12

The makers of Sweet-Things candy sell their candy by the box.Based on company policy,the mean target weight of all boxes is 2.0 pounds.To make sure that they are not putting too much in the boxes,the manager wants no more than 3 percent of all boxes to contain more than 2.10 pounds of candy.In order to do this,with a mean weight of 2 pounds,what must the standard deviation be? Assume that the box weights are normally distributed.

Accepted Answer

A) Approximately 0.05 pounds 
B) -0.133 pounds 
C) 1.144 pounds 
D) None of the above 
A) Approximately 0.05 pounds 
B) -0.133 pounds 
C) 1.144 pounds 
D) None of the above

Question 13

For a standardized normal distribution,calculate P(-1.00 < z < 1.00).

Accepted Answer

A) 0.6826 
B) 0.6667 
C) 0.4572 
D) 0.5521 
A) 0.6826 
B) 0.6667 
C) 0.4572 
D) 0.5521

Question 14

The State Department of Forests has determined that annual tree growth in a particular forest area is normally distributed with a mean equal to 17 inches and a standard deviation equal to 6 inches.If 2 trees are randomly chosen,the probability that both trees will have grown more than 20 inches during the year is approximately .037.

Accepted Answer

A) True 
 B)False

Question 15

Consider a random variable,z,that has a standardized normal distribution.Determine P(z > -1).

Accepted Answer

A) 0.8413 
B) 0.1251 
C) 0.1512 
D) 0.2124 
A) 0.8413 
B) 0.1251 
C) 0.1512 
D) 0.2124

Question 16

Consider a random variable,z,that has a standardized normal distribution.Determine P (1.28 < z < 2.33).

Accepted Answer

A) 0.0126 
B) 0.3997 
C) 0.0904 
D) 0.4901 
A) 0.0126 
B) 0.3997 
C) 0.0904 
D) 0.4901

Question 17

The weight of sacks of potatoes is normally distributed with a mean of 20 pounds and a standard deviation of 2 pounds.The weight of sacks of onions is also normally distributed with a mean of 20 pounds and a standard deviation of 0.50 pounds.Based on this information,which product will yield the highest probability of getting a very heavy sack?

Accepted Answer

Since both products have the same mean a

Question 18

The amount of drying time for the paint applied to a plastic component part is thought to be uniformly distributed between 30 and 60 minutes.Currently,the automated process selects the part from the drying bin after the part has been there for 50 minutes.The probability that none of three parts picked are still wet when they are selected is approximately 0.04.

Accepted Answer

A) True 
 B)False

Question 19

Which of the following is not a characteristic of the normal distribution?

Accepted Answer

A) Symmetric 
B) Mean = median = mode 
C) Bell-shaped 
D) Equal probabilities at all values of x 
A) Symmetric 
B) Mean = median = mode 
C) Bell-shaped 
D) Equal probabilities at all values of x

Question 20

If a uniform distribution and normal distribution both have the same mean and the same range,the normal distribution will have a larger standard deviation than the uniform distribution

Accepted Answer

A) True 
 B)False

For a standardized normal distribution,calculate P(z < 1.5).

In a standard normal distribution,the probability that z is greater than 0 is:

A professor noted that the grades of his students were normally distributed with a mean of 75.07 and a standard deviation of 11.65.If only 10 percent of the students received grades of A,what is the minimum score needed to receive an A?

A random variable is normally distributed with a mean of 25 and a standard deviation of 5.If an observation is randomly selected from the distribution,determine two values of which the smallest has 25% of the values below it and the largest has 25% of the values above it.

Consider a random variable,z,that has a standardized normal distribution.Determine (-2 ≤ z ≤ 3).

Which of the following probability distributions can be used to describe the distribution for a continuous random variable?

It has been determined the weight of bricks made by the Dillenger Stone Company is uniformly distributed between 1 and 1.5 pounds.Based on this information,the probability that two randomly selected bricks will each weigh more than 1.3 pounds is 0.16.

For a standardized normal distribution,calculate P(-1.00 < z < 1.00).

Consider a random variable,z,that has a standardized normal distribution.Determine P(z > -1).

Consider a random variable,z,that has a standardized normal distribution.Determine P (1.28 < z < 2.33).

Which of the following is not a characteristic of the normal distribution?

If a uniform distribution and normal distribution both have the same mean and the same range,the normal distribution will have a larger standard deviation than the uniform distribution

The Where,Why,and How of Data Collection

Graphs,Charts and Tablesdescribing Your Data

Describing Data Using Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Introduction to Sampling Distributions

Estimating Single Population Parameters

Introduction to Hypothesis Testing

Estimation and Hypothesis Testing for Two Population Parameters

Hypothesis Tests and Estimation for Population Variances

Analysis of Variance

Goodness-Of-Fit Tests and Contingency Analysis

Introduction to Linear Regression and Correlation Analysis

Multiple Regression Analysis and Model Building

Analyzing and Forecasting Time-Series Data

Introduction to Nonparametric Statistics

Introduction to Quality and Statistical Process Control

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Exam 6: Introduction to Continuous Probability Distributions

For a standardized normal distribution,calculate P(z < 1.5).

In a standard normal distribution,the probability that z is greater than 0 is:

A professor noted that the grades of his students were normally distributed with a mean of 75.07 and a standard deviation of 11.65.If only 10 percent of the students received grades of A,what is the minimum score needed to receive an A?

A random variable is normally distributed with a mean of 25 and a standard deviation of 5.If an observation is randomly selected from the distribution,determine two values of which the smallest has 25% of the values below it and the largest has 25% of the values above it.

Consider a random variable,z,that has a standardized normal distribution.Determine (-2 ≤ z ≤ 3).

Which of the following probability distributions can be used to describe the distribution for a continuous random variable?

It has been determined the weight of bricks made by the Dillenger Stone Company is uniformly distributed between 1 and 1.5 pounds.Based on this information,the probability that two randomly selected bricks will each weigh more than 1.3 pounds is 0.16.

For a standardized normal distribution,calculate P(-1.00 < z < 1.00).

Consider a random variable,z,that has a standardized normal distribution.Determine P(z > -1).

Consider a random variable,z,that has a standardized normal distribution.Determine P (1.28 < z < 2.33).

Which of the following is not a characteristic of the normal distribution?

If a uniform distribution and normal distribution both have the same mean and the same range,the normal distribution will have a larger standard deviation than the uniform distribution

The Where,Why,and How of Data Collection

Graphs,Charts and Tablesdescribing Your Data

Describing Data Using Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Introduction to Sampling Distributions

Estimating Single Population Parameters

Introduction to Hypothesis Testing

Estimation and Hypothesis Testing for Two Population Parameters

Hypothesis Tests and Estimation for Population Variances

Analysis of Variance

Goodness-Of-Fit Tests and Contingency Analysis

Introduction to Linear Regression and Correlation Analysis

Multiple Regression Analysis and Model Building

Analyzing and Forecasting Time-Series Data

Introduction to Nonparametric Statistics

Introduction to Quality and Statistical Process Control

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