Question 1

The weight of a product is normally distributed with a mean of four grams and a variance of .25 "squared grams." What is the probability that a randomly selected unit from a recently manufactured batch weighs:
-More than 3.75 grams?

Accepted Answer

The answer of The weight of a product is normally...

Question 2

A probability distribution that is useful in describing the time or space between successive occurrences of an event is the _______ probability distribution.

Accepted Answer

A) uniform 
B) normal 
C) Poisson 
D) exponential 
E) binomial

Question 3

Find z when the area to the right of z is .1314

Accepted Answer

The answer of Find z when the area to the...

Question 4

Suppose the distribution of personality test scores is normally distributed with a mean of 15 and a variance of 25.
-If X is an exponential random variable,then the probability X falls below its mean value is _____.

Accepted Answer

The answer of Suppose the distribution of personality test scores...

Question 5

While conducting experiments, a marine biologist selects water depths from a uniformly distributed collection that vary between 2.00 m and 7.00 m.
-What is the probability that a randomly selected depth is between 2.25 m and 5.00 m?

Accepted Answer

The answer of While conducting experiments, a marine biologist selects...

Question 6

At a Great Lakes nuclear power plant, lake water is used as part of the cooling system. This raises the temperature of the water that is discharged back into the lake. The amount that the water temperature is raised has a uniform distribution over the interval from 10 to 25º C.
-What is the standard deviation of the temperature increase?

Accepted Answer

The answer of At a Great Lakes nuclear power plant,...

Question 7

In a statistical study,the random variable X = 1,if the house is colonial,and X = 0 if the house is not colonial,then it is appropriate to model this variable with a continuous probability distribution.

Accepted Answer

A) True 
 B)False

Question 8

The mean of a standard normal distribution is always equal to 1.

Accepted Answer

A) True 
 B)False

Question 9

The price of an energy sports drink is normally distributed with an average of $2.25 and a standard deviation of $0.15 across store outlets.
-What is the probability that a randomly selected drink will cost between $2.00 and $3.00?

Accepted Answer

The answer of The price of an energy sports drink...

Question 10

If the random variable of x is normally distributed,____ % of all possible observed values of x will be within two standard deviations of the mean.

Accepted Answer

The answer of If the random variable of x is...

Question 11

At a Great Lakes nuclear power plant, lake water is used as part of the cooling system. This raises the temperature of the water that is discharged back into the lake. The amount that the water temperature is raised has a uniform distribution over the interval from 10 to 25º C.
-Suppose that a temperature increase of more than 18 º C is considered to be potentially dangerous to the environment.What is the probability that at any point of time,the temperature increase is potentially dangerous?

Accepted Answer

The answer of At a Great Lakes nuclear power plant,...

Question 12

The weight of a product is normally distributed with a mean of four grams and a variance of .25 "squared grams." What is the probability that a randomly selected unit from a recently manufactured batch weighs:
-The weight of a product is normally distributed with a standard deviation of .5 grams.What should the average weight be if the production manager wants no more than 10% of the products to weigh more than 4.8 grams?

Accepted Answer

The answer of The weight of a product is normally...

Question 13

Is no more than 3 minutes?

Accepted Answer

A) 3012 
B) 6988 
C) 4346 
D) 5654 
E) 0821

Question 14

What is the probability that the temperature increase will be less than 20º C?

Accepted Answer

The answer of What is the probability that the temperature...

Question 15

Suppose that in an effort to provide better service to the public,the manager of the pizza delivery service is permitted to provide discounts to those individuals whose waiting time exceeds a predetermined time.The director decides that 15% of the customers should receive this discount.What are the number of minutes they need to wait to receive the discount?

Accepted Answer

The answer of Suppose that in an effort to provide...

Question 16

The time of travel from a person's apartment to the bus station follows a uniform distribution over the interval from 20 to 30 minutes.If they leave home at 9:05 AM,what is the probability that they will get to the station between 9:25 and 9:30 AM?

Accepted Answer

The answer of The time of travel from a person's...

Question 17

Suppose that the waiting time for a pizza to be delivered to an individual's residence has been found to be normally distributed with a mean of 30 minutes and a standard deviation of 8 minutes. What is the probability that a randomly selected individual will have a waiting time
-Between 15 and 45 minutes

Accepted Answer

The answer of Suppose that the waiting time for a...

Question 18

_____________ values of the standard deviation results in a normal curve that is narrower and more peaked.

Accepted Answer

The answer of _____________ values of the standard deviation results...

Question 19

The fill weight of a certain brand of adult cereal is normally distributed with a mean of 910 grams and a standard deviation of 5 grams.
-We calculated the value of z for a specific box of this brand of cereal and the z value was negative.This negative z value indicates that:

Accepted Answer

A) We made a mistake in our calculations,as z must always be a nonnegative number. 
B) The fill weight exceeds 910 grams. 
C) The fill weight is less than 910 grams 
D) The fill weight is equal to 910 grams 
E) The fill weight may be more or less than 910 grams depending on the value of the standard deviation.

Question 20

The mean and median are the same for an exponential distribution.

Accepted Answer

A) True 
 B)False

Exam 5: Continuous Random Variables

The weight of a product is normally distributed with a mean of four grams and a variance of .25 "squared grams." What is the probability that a randomly selected unit from a recently manufactured batch weighs: -More than 3.75 grams?

A probability distribution that is useful in describing the time or space between successive occurrences of an event is the _______ probability distribution.

Find z when the area to the right of z is .1314

Suppose the distribution of personality test scores is normally distributed with a mean of 15 and a variance of 25. -If X is an exponential random variable,then the probability X falls below its mean value is _____.

While conducting experiments, a marine biologist selects water depths from a uniformly distributed collection that vary between 2.00 m and 7.00 m. -What is the probability that a randomly selected depth is between 2.25 m and 5.00 m?

In a statistical study,the random variable X = 1,if the house is colonial,and X = 0 if the house is not colonial,then it is appropriate to model this variable with a continuous probability distribution.

The mean of a standard normal distribution is always equal to 1.

The price of an energy sports drink is normally distributed with an average of $2.25 and a standard deviation of $0.15 across store outlets. -What is the probability that a randomly selected drink will cost between $2.00 and $3.00?

If the random variable of x is normally distributed,____ % of all possible observed values of x will be within two standard deviations of the mean.

Is no more than 3 minutes?

What is the probability that the temperature increase will be less than 20º C?

The time of travel from a person's apartment to the bus station follows a uniform distribution over the interval from 20 to 30 minutes.If they leave home at 9:05 AM,what is the probability that they will get to the station between 9:25 and 9:30 AM?

_____________ values of the standard deviation results in a normal curve that is narrower and more peaked.

The fill weight of a certain brand of adult cereal is normally distributed with a mean of 910 grams and a standard deviation of 5 grams. -We calculated the value of z for a specific box of this brand of cereal and the z value was negative.This negative z value indicates that:

The mean and median are the same for an exponential distribution.