Question 1

The triangular distribution T(0, 10, 20) has a standard deviation of:

Accepted Answer

A) 4.082. 
B) 3.775. 
C) 3.024. 
D) 2.994. 
A) 4.082. 
B) 3.775. 
C) 3.024. 
D) 2.994.

Question 2

Normal distributions differ only in their means and variances.

Accepted Answer

A) True 
 B)False

Question 3

A machine dispenses water into a glass. Assuming that the amount of water dispensed follows a continuous uniform distribution from 10 ounces to 16 ounces, the standard deviation of the amount of water dispensed is about:

Accepted Answer

A) 1.73 ounces. 
B) 3.00 ounces. 
C) 0.57 ounce. 
D) 3.51 ounces. 
A) 1.73 ounces. 
B) 3.00 ounces. 
C) 0.57 ounce. 
D) 3.51 ounces.

Question 4

If the random variable Z has a standard normal distribution, then P(1.17 ≤ Z ≤ 2.26) is:

Accepted Answer

A) 0.1091. 
B) 0.1203. 
C) 0.2118. 
D) 0.3944. 
A) 0.1091. 
B) 0.1203. 
C) 0.2118. 
D) 0.3944.

Question 5

If arrivals occur at a mean rate of 3.6 events per hour, the exponential probability of waiting more than 0.5 hour for the next arrival is:

Accepted Answer

A) .2407. 
B) .1653. 
C) .1222. 
D) .5000. 
A) .2407. 
B) .1653. 
C) .1222. 
D) .5000.

Question 6

A certain assembly line at Vexing Manufacturing Company averages 30 minutes between breakdowns. The median time between breakdowns is:

Accepted Answer

A) 30.0 minutes. 
B) 35.7 minutes. 
C) 25.4 minutes. 
D) 20.8 minutes. 
A) 30.0 minutes. 
B) 35.7 minutes. 
C) 25.4 minutes. 
D) 20.8 minutes.

Question 7

The variable in a normal distribution can assume any value between

Accepted Answer

A) -3 and +3. 
B) -4 and +4. 
C) -1 and +1. 
D) -∞ and +∞. 
A) -3 and +3. 
B) -4 and +4. 
C) -1 and +1. 
D) -∞ and +∞.

Question 8

Light bulbs are normally distributed with an average lifetime of 1000 hours and a standard deviation of 250 hours. The probability that a light bulb picked at random will last less than 1500 hours is about:

Accepted Answer

A) 97.72 percent. 
B) 95.44 percent. 
C) 75.00 percent. 
D) 68.00 percent. 
A) 97.72 percent. 
B) 95.44 percent. 
C) 75.00 percent. 
D) 68.00 percent.

Question 9

The exponential distribution can be either right-skewed or left-skewed, depending on λ

Accepted Answer

A) True 
 B)False

Question 10

If adult male heights are normally distributed with a mean of 180 cm and a standard deviation of 7 cm, how high should an aircraft lavatory door be to ensure that 99.9 percent of adult males will not have to stoop as they enter?

Accepted Answer

A) 195.7 cm 
B) 201.6 cm 
C) 207.3 cm 
D) 201.4 cm 
A) 195.7 cm 
B) 201.6 cm 
C) 207.3 cm 
D) 201.4 cm

Question 11

Experience suggests that 4 percent of all college students had a tonsillectomy. In a sample of 300 college students, we need to find the probability that at least 10 had a tonsillectomy. It is acceptable to use the normal distribution to estimate this probability.

Accepted Answer

A) True 
 B)False

Question 12

The ages of job applicants for a security guard position are uniformly distributed between 25 and 65. Could a 25-year-old job applicant be two standard deviations below the mean (or more than two standard deviations)?

Accepted Answer

A) Yes. 
B) No. 
C) Impossible to determine from given information. 
A) Yes. 
B) No. 
C) Impossible to determine from given information.

Question 13

A software developer makes 175 phone calls to its current customers. There is an 8 percent chance of reaching a given customer (instead of a busy signal, no answer, or answering machine). The normal approximation of the probability of reaching at least 20 customers is:

Accepted Answer

A) .022. 
B) .007. 
C) .063. 
D) .937. 
A) .022. 
B) .007. 
C) .063. 
D) .937.

Question 14

The figure shows a standard normal N(0, 1) distribution. Find the shaded area.   C.2 gives 1 - P(z < -2.17) = 1 - .0150 = 0.9750 =1-NORM.S.DIST(-2.17,1).

Accepted Answer

A) .6444 
B) .7514 
C) .9245 
D) 0.9850 
A) .6444 
B) .7514 
C) .9245 
D) 0.9850

Question 15

The normal distribution is a good approximation to the binomial if n = 25 and π = .50.

Accepted Answer

A) True 
 B)False

Question 16

Bob's z-score for the last exam was -1.15 in FIN 417, "Capital Budgeting Strategies." Bob said, "Yipe! My score is within the bottom quartile." Assuming a normal distribution, is Bob right?

Accepted Answer

A) Yes 
B) No 
C) Must know the class size to answer 
A) Yes 
B) No 
C) Must know the class size to answer

Question 17

Bob's z-score for the last exam was 1.52 in Prof. Axolotl's class BIO 417, "Life Cycle of the Ornithorhynchus." Bob said, "Oh, good, my score is in the top 10 percent." Assuming a normal distribution of scores, is Bob right?

Accepted Answer

A) Yes. 
B) No. 
C) Must have n to answer. 
A) Yes. 
B) No. 
C) Must have n to answer.

Question 18

Excel's =RAND() function produces random numbers that are uniformly distributed between 0 and 1. The mean of this distribution is approximately

Accepted Answer

A) .5000. 
B) .2500. 
C) .3333. 
D) .2887. 
A) .5000. 
B) .2500. 
C) .3333. 
D) .2887.

Question 19

Could this function be a PDF?

Accepted Answer

A) Yes. 
B) No. 
C) It depends on x. 
A) Yes. 
B) No. 
C) It depends on x.

Question 20

If the random variable Z has a standard normal distribution, then P(Z ≤ -1.72) is:

Accepted Answer

A) 0.9573. 
B) 0.0446. 
C) 0.5016. 
D) 0.0427. 
A) 0.9573. 
B) 0.0446. 
C) 0.5016. 
D) 0.0427.

The triangular distribution T(0, 10, 20) has a standard deviation of:

Normal distributions differ only in their means and variances.

A machine dispenses water into a glass. Assuming that the amount of water dispensed follows a continuous uniform distribution from 10 ounces to 16 ounces, the standard deviation of the amount of water dispensed is about:

If the random variable Z has a standard normal distribution, then P(1.17 ≤ Z ≤ 2.26) is:

If arrivals occur at a mean rate of 3.6 events per hour, the exponential probability of waiting more than 0.5 hour for the next arrival is:

A certain assembly line at Vexing Manufacturing Company averages 30 minutes between breakdowns. The median time between breakdowns is:

The variable in a normal distribution can assume any value between

Light bulbs are normally distributed with an average lifetime of 1000 hours and a standard deviation of 250 hours. The probability that a light bulb picked at random will last less than 1500 hours is about:

The exponential distribution can be either right-skewed or left-skewed, depending on λ

If adult male heights are normally distributed with a mean of 180 cm and a standard deviation of 7 cm, how high should an aircraft lavatory door be to ensure that 99.9 percent of adult males will not have to stoop as they enter?

Experience suggests that 4 percent of all college students had a tonsillectomy. In a sample of 300 college students, we need to find the probability that at least 10 had a tonsillectomy. It is acceptable to use the normal distribution to estimate this probability.

The ages of job applicants for a security guard position are uniformly distributed between 25 and 65. Could a 25-year-old job applicant be two standard deviations below the mean (or more than two standard deviations)?

A software developer makes 175 phone calls to its current customers. There is an 8 percent chance of reaching a given customer (instead of a busy signal, no answer, or answering machine). The normal approximation of the probability of reaching at least 20 customers is:

The figure shows a standard normal N(0, 1) distribution. Find the shaded area. C.2 gives 1 - P(z < -2.17) = 1 - .0150 = 0.9750 =1-NORM.S.DIST(-2.17,1).

The normal distribution is a good approximation to the binomial if n = 25 and π = .50.

Bob's z-score for the last exam was -1.15 in FIN 417, "Capital Budgeting Strategies." Bob said, "Yipe! My score is within the bottom quartile." Assuming a normal distribution, is Bob right?

Bob's z-score for the last exam was 1.52 in Prof. Axolotl's class BIO 417, "Life Cycle of the Ornithorhynchus." Bob said, "Oh, good, my score is in the top 10 percent." Assuming a normal distribution of scores, is Bob right?

Excel's =RAND() function produces random numbers that are uniformly distributed between 0 and 1. The mean of this distribution is approximately

Could this function be a PDF?

If the random variable Z has a standard normal distribution, then P(Z ≤ -1.72) is:

Overview of Statistics

Data Collection

Describing Data Visually

Descriptive Statistics

Probability

Discrete Probability Distributions

Sampling Distributions and Estimation

One-Sample Hypothesis Tests

Two-Sample Hypothesis Tests

Analysis of Variance

Simple Regression

Multiple Regression

Time Series Analysis

Chi-Square Tests

Nonparametric Tests

Quality Management

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Exam 7: Continuous Probability Distributions

The triangular distribution T(0, 10, 20) has a standard deviation of:

Normal distributions differ only in their means and variances.

A machine dispenses water into a glass. Assuming that the amount of water dispensed follows a continuous uniform distribution from 10 ounces to 16 ounces, the standard deviation of the amount of water dispensed is about:

If the random variable Z has a standard normal distribution, then P(1.17 ≤ Z ≤ 2.26) is:

If arrivals occur at a mean rate of 3.6 events per hour, the exponential probability of waiting more than 0.5 hour for the next arrival is:

A certain assembly line at Vexing Manufacturing Company averages 30 minutes between breakdowns. The median time between breakdowns is:

The variable in a normal distribution can assume any value between

Light bulbs are normally distributed with an average lifetime of 1000 hours and a standard deviation of 250 hours. The probability that a light bulb picked at random will last less than 1500 hours is about:

The exponential distribution can be either right-skewed or left-skewed, depending on λ

If adult male heights are normally distributed with a mean of 180 cm and a standard deviation of 7 cm, how high should an aircraft lavatory door be to ensure that 99.9 percent of adult males will not have to stoop as they enter?

Experience suggests that 4 percent of all college students had a tonsillectomy. In a sample of 300 college students, we need to find the probability that at least 10 had a tonsillectomy. It is acceptable to use the normal distribution to estimate this probability.

The ages of job applicants for a security guard position are uniformly distributed between 25 and 65. Could a 25-year-old job applicant be two standard deviations below the mean (or more than two standard deviations)?

A software developer makes 175 phone calls to its current customers. There is an 8 percent chance of reaching a given customer (instead of a busy signal, no answer, or answering machine). The normal approximation of the probability of reaching at least 20 customers is:

The figure shows a standard normal N(0, 1) distribution. Find the shaded area. C.2 gives 1 - P(z < -2.17) = 1 - .0150 = 0.9750 =1-NORM.S.DIST(-2.17,1).

The normal distribution is a good approximation to the binomial if n = 25 and π = .50.

Bob's z-score for the last exam was -1.15 in FIN 417, "Capital Budgeting Strategies." Bob said, "Yipe! My score is within the bottom quartile." Assuming a normal distribution, is Bob right?

Bob's z-score for the last exam was 1.52 in Prof. Axolotl's class BIO 417, "Life Cycle of the Ornithorhynchus." Bob said, "Oh, good, my score is in the top 10 percent." Assuming a normal distribution of scores, is Bob right?

Excel's =RAND() function produces random numbers that are uniformly distributed between 0 and 1. The mean of this distribution is approximately

Could this function be a PDF?

If the random variable Z has a standard normal distribution, then P(Z ≤ -1.72) is:

Overview of Statistics

Data Collection

Describing Data Visually

Descriptive Statistics

Probability

Discrete Probability Distributions

Sampling Distributions and Estimation

One-Sample Hypothesis Tests

Two-Sample Hypothesis Tests

Analysis of Variance

Simple Regression

Multiple Regression

Time Series Analysis

Chi-Square Tests

Nonparametric Tests

Quality Management

Filters