Question 1

The z-scores for X values greater than the mean are negative.

Accepted Answer

A) True 
 B)False  False

Question 2

A study of a company's practice regarding the payment of invoices revealed that an invoice was paid an average of 20 days after it was received. The standard deviation equaled five days. Assuming that the distribution is normal,what percent of the invoices were paid within 15 days of receipt?

Accepted Answer

A) 15.87% 
B) 37.91% 
C) 34.13% 
D) 86.74% 
A) 15.87% 
B) 37.91% 
C) 34.13% 
D) 86.74% A

Question 3

The time to fly between New York City and Chicago is uniformly distributed with a minimum of 120 minutes and a maximum of 150 minutes. What is the probability that a flight is more than 140 minutes?

Accepted Answer

A) 1.00 
B) 0.50 
C) 0.333 
D) 0.00 
A) 1.00 
B) 0.50 
C) 0.333 
D) 0.00 C

Question 4

A binomial distribution has 50 trials (n = 50)with a probability of success of 0.50 (π = 0.50). We would like to find the probability of 34 or more successes using the normal distribution to approximate the binomial. Applying the continuity correction factor,what z-score should be used?

Accepted Answer

A) 2.404 
B) 2.546 
C) 2.687 
D) 0.50 
A) 2.404 
B) 2.546 
C) 2.687 
D) 0.50

Question 5

For a normal distribution,what is the likelihood (expressed as a percentage)that a random variable is within plus and minus two standard deviations of the mean?

Accepted Answer

A) 68.26% 
B) 99.74% 
C) 34.13% 
D) 95.44% 
A) 68.26% 
B) 99.74% 
C) 34.13% 
D) 95.44%

Question 6

Which of the following is a characteristic of the normal probability distribution?

Accepted Answer

A) It's positively skewed. 
B) It's bell-shaped. 
C) It's asymmetrical. 
D) It's rectangular. 
A) It's positively skewed. 
B) It's bell-shaped. 
C) It's asymmetrical. 
D) It's rectangular.

Question 7

If an average of 12 customers are served per hour,what is the probability that the next customer will arrive in 3 minutes or less?

Accepted Answer

A) 0.55 
B) 0.30 
C) 0.45 
D) 0.39 
A) 0.55 
B) 0.30 
C) 0.45 
D) 0.39

Question 8

What is the probability that z is between 0.0 and 2.0?

Accepted Answer

A) 1.0000 
B) 0.7408 
C) 0.1359 
D) 0.4772 
A) 1.0000 
B) 0.7408 
C) 0.1359 
D) 0.4772

Question 9

Within plus and minus one standard deviation of the mean,the area under any normal curve is about 68%.

Accepted Answer

A) True 
 B)False

Question 10

Nonstop Airlines determined that the mean number of passengers per flight is 152 with a standard deviation of 10 passengers. Practically all flights have between 142 and 162 passengers.

Accepted Answer

A) True 
 B)False

Question 11

The weekly incomes of a large group of executives are normally distributed with a mean of $2,000 and a standard deviation of $100. What is the z-score for an income of $2,100?

Accepted Answer

A) 1.00 
B) 2.00 
C) 1.683 
D) −0.90 
A) 1.00 
B) 2.00 
C) 1.683 
D) −0.90

Question 12

A binomial distribution has 100 trials (n = 100)with a probability of success of 0.25 (π = 0.25). To apply the normal distribution to approximate the binomial,what are the mean and standard deviation?

Accepted Answer

A) µ= 100 and σ = 0.25 
B) µ = 25 and σ = 100 
C) µ = 25 and σ = 4.33 
D) µ= 100 and σ = 2500 
A) µ= 100 and σ = 0.25 
B) µ = 25 and σ = 100 
C) µ = 25 and σ = 4.33 
D) µ= 100 and σ = 2500

Question 13

The average score of 100 students taking a statistics final was 70,with a standard deviation of 7. Assuming a normal distribution,what is the probability that a student scored 90 or higher?

Accepted Answer

A) 0.4979 
B) 0.0021 
C) 0.9979 
D) 2.86 
A) 0.4979 
B) 0.0021 
C) 0.9979 
D) 2.86

Question 14

The weight of cans of fruit is normally distributed with a mean of 1,000 grams and a standard deviation of 50 grams. What percent of the cans weigh 860 grams or less?

Accepted Answer

A) 0.0100 
B) 0.8400 
C) 0.0026 
D) 0.0001 
A) 0.0100 
B) 0.8400 
C) 0.0026 
D) 0.0001

Question 15

The employees of Cartwright Manufacturing are awarded efficiency ratings. The distribution of the ratings approximates a normal distribution. The mean is 400,the standard deviation is 50. What is the area under the normal curve between 400 and 482?

Accepted Answer

A) 0.5000 
B) 0.4495 
C) 0.3413 
D) 0.4750 
A) 0.5000 
B) 0.4495 
C) 0.3413 
D) 0.4750

Question 16

The average score of 100 students taking a statistics final was 70,with a standard deviation of 7. Assuming a normal distribution,what test score separates the top 5% of the students from the lower 95% of the students?

Accepted Answer

A) 81.55 
B) 90.00 
C) 83.72 
D) 78.96 
A) 81.55 
B) 90.00 
C) 83.72 
D) 78.96

Question 17

For the normal distribution,the mean plus and minus two standard deviations will include about what percent of the observations?

Accepted Answer

A) 50% 
B) 99.7% 
C) 95% 
D) 68% 
A) 50% 
B) 99.7% 
C) 95% 
D) 68%

Question 18

A binomial distribution has 50 trials (n = 50)with a probability of success of 0.50 (π = 0.50). To use the normal distribution to approximate the binomial,what are the mean and standard deviation?

Accepted Answer

A) µ = 25 and σ = 3.5355 
B) µ = 25 and σ = 12.5 
C) µ = 25 and σ = 4.33 
D) µ = 50 and σ = 100 
A) µ = 25 and σ = 3.5355 
B) µ = 25 and σ = 12.5 
C) µ = 25 and σ = 4.33 
D) µ = 50 and σ = 100

Question 19

The mean of a normal distribution is 400 pounds. The standard deviation is 10 pounds. What is the probability of a weight between 415 pounds and the mean of 400 pounds?

Accepted Answer

A) 0.5000 
B) 0.1932 
C) 0.4332 
D) 0.3413 
A) 0.5000 
B) 0.1932 
C) 0.4332 
D) 0.3413

Question 20

If an average of 12 customers are served per hour,then one customer arrives every ________.

Accepted Answer

A) 12 minutes 
B) 60 minutes 
C) 5 minutes 
D) 10 minutes 
A) 12 minutes 
B) 60 minutes 
C) 5 minutes 
D) 10 minutes

The z-scores for X values greater than the mean are negative.

A study of a company's practice regarding the payment of invoices revealed that an invoice was paid an average of 20 days after it was received. The standard deviation equaled five days. Assuming that the distribution is normal,what percent of the invoices were paid within 15 days of receipt?

The time to fly between New York City and Chicago is uniformly distributed with a minimum of 120 minutes and a maximum of 150 minutes. What is the probability that a flight is more than 140 minutes?

A binomial distribution has 50 trials (n = 50)with a probability of success of 0.50 (π = 0.50). We would like to find the probability of 34 or more successes using the normal distribution to approximate the binomial. Applying the continuity correction factor,what z-score should be used?

For a normal distribution,what is the likelihood (expressed as a percentage)that a random variable is within plus and minus two standard deviations of the mean?

Which of the following is a characteristic of the normal probability distribution?

If an average of 12 customers are served per hour,what is the probability that the next customer will arrive in 3 minutes or less?

What is the probability that z is between 0.0 and 2.0?

Within plus and minus one standard deviation of the mean,the area under any normal curve is about 68%.

Nonstop Airlines determined that the mean number of passengers per flight is 152 with a standard deviation of 10 passengers. Practically all flights have between 142 and 162 passengers.

The weekly incomes of a large group of executives are normally distributed with a mean of $2,000 and a standard deviation of $100. What is the z-score for an income of $2,100?

A binomial distribution has 100 trials (n = 100)with a probability of success of 0.25 (π = 0.25). To apply the normal distribution to approximate the binomial,what are the mean and standard deviation?

The average score of 100 students taking a statistics final was 70,with a standard deviation of 7. Assuming a normal distribution,what is the probability that a student scored 90 or higher?

The weight of cans of fruit is normally distributed with a mean of 1,000 grams and a standard deviation of 50 grams. What percent of the cans weigh 860 grams or less?

The employees of Cartwright Manufacturing are awarded efficiency ratings. The distribution of the ratings approximates a normal distribution. The mean is 400,the standard deviation is 50. What is the area under the normal curve between 400 and 482?

The average score of 100 students taking a statistics final was 70,with a standard deviation of 7. Assuming a normal distribution,what test score separates the top 5% of the students from the lower 95% of the students?

For the normal distribution,the mean plus and minus two standard deviations will include about what percent of the observations?

A binomial distribution has 50 trials (n = 50)with a probability of success of 0.50 (π = 0.50). To use the normal distribution to approximate the binomial,what are the mean and standard deviation?

The mean of a normal distribution is 400 pounds. The standard deviation is 10 pounds. What is the probability of a weight between 415 pounds and the mean of 400 pounds?

If an average of 12 customers are served per hour,then one customer arrives every ________.

What Is Statistics

Describing Data: Frequency Tables, Frequency Distributions, and Graphic Presentation

Describing Data: Numerical Measures

Describing Data: Displaying and Exploring Data

A Survey of Probability Concepts

Discrete Probability Distributions

Sampling Methods and the Central Limit Theorem

Estimation and Confidence Intervals

One-Sample Tests of Hypothesis

Two-Sample Tests of Hypothesis

Analysis of Variance

Correlation and Linear Regression

Multiple Regression Analysis

Nonparametric Methods: Nominal Level Hypothesis Tests

Nonparametric Methods: Analysis of Ordinal Data

Index Numbers

Time Series and Forecasting

Statistical Process Control and Quality Management

An Introduction to Decision Theory

Filters

Exam 7: Continuous Probability Distributions

The z-scores for X values greater than the mean are negative.

A study of a company's practice regarding the payment of invoices revealed that an invoice was paid an average of 20 days after it was received. The standard deviation equaled five days. Assuming that the distribution is normal,what percent of the invoices were paid within 15 days of receipt?

The time to fly between New York City and Chicago is uniformly distributed with a minimum of 120 minutes and a maximum of 150 minutes. What is the probability that a flight is more than 140 minutes?

A binomial distribution has 50 trials (n = 50)with a probability of success of 0.50 (π = 0.50). We would like to find the probability of 34 or more successes using the normal distribution to approximate the binomial. Applying the continuity correction factor,what z-score should be used?

For a normal distribution,what is the likelihood (expressed as a percentage)that a random variable is within plus and minus two standard deviations of the mean?

Which of the following is a characteristic of the normal probability distribution?

If an average of 12 customers are served per hour,what is the probability that the next customer will arrive in 3 minutes or less?

What is the probability that z is between 0.0 and 2.0?

Within plus and minus one standard deviation of the mean,the area under any normal curve is about 68%.

Nonstop Airlines determined that the mean number of passengers per flight is 152 with a standard deviation of 10 passengers. Practically all flights have between 142 and 162 passengers.

The weekly incomes of a large group of executives are normally distributed with a mean of $2,000 and a standard deviation of $100. What is the z-score for an income of $2,100?

A binomial distribution has 100 trials (n = 100)with a probability of success of 0.25 (π = 0.25). To apply the normal distribution to approximate the binomial,what are the mean and standard deviation?

The average score of 100 students taking a statistics final was 70,with a standard deviation of 7. Assuming a normal distribution,what is the probability that a student scored 90 or higher?

The weight of cans of fruit is normally distributed with a mean of 1,000 grams and a standard deviation of 50 grams. What percent of the cans weigh 860 grams or less?

The employees of Cartwright Manufacturing are awarded efficiency ratings. The distribution of the ratings approximates a normal distribution. The mean is 400,the standard deviation is 50. What is the area under the normal curve between 400 and 482?

The average score of 100 students taking a statistics final was 70,with a standard deviation of 7. Assuming a normal distribution,what test score separates the top 5% of the students from the lower 95% of the students?

For the normal distribution,the mean plus and minus two standard deviations will include about what percent of the observations?

A binomial distribution has 50 trials (n = 50)with a probability of success of 0.50 (π = 0.50). To use the normal distribution to approximate the binomial,what are the mean and standard deviation?

The mean of a normal distribution is 400 pounds. The standard deviation is 10 pounds. What is the probability of a weight between 415 pounds and the mean of 400 pounds?

If an average of 12 customers are served per hour,then one customer arrives every ________.

What Is Statistics

Describing Data: Frequency Tables, Frequency Distributions, and Graphic Presentation

Describing Data: Numerical Measures

Describing Data: Displaying and Exploring Data

A Survey of Probability Concepts

Discrete Probability Distributions

Sampling Methods and the Central Limit Theorem

Estimation and Confidence Intervals

One-Sample Tests of Hypothesis

Two-Sample Tests of Hypothesis

Analysis of Variance

Correlation and Linear Regression

Multiple Regression Analysis

Nonparametric Methods: Nominal Level Hypothesis Tests

Nonparametric Methods: Analysis of Ordinal Data

Index Numbers

Time Series and Forecasting

Statistical Process Control and Quality Management

An Introduction to Decision Theory

Filters