Math 1280 Final Exam/ Quizzes with Correct
Ans/ 2025.
You are interested in the number of English-speaking people on the planet who want to play a
new kind of online video game. You asked 300 college students if they were interested in playing
video games, 100 said yes, and of them 20 preferred your game to an existing game that is
widely used. How many people were in the sample?
Select one: a. The number of English-speaking people on the planet who want to play a new
kind of online video game. b. 300 c. 200 d. 100 e. 20 - Answer: b
What is the mean of x? x <- c(12, 14, 11, 14, 13, 15, 12, 16, 10)
Select one: a. 12 b. 13 c. 14 d. 15 e. 16 - Answer: b
The mean weekly sales per employee at a nationwide store is normally distributed with a mean
of $7,300 per week and a standard deviation of $700. What is the probability that a randomly
selected employee will have sales less than $6,500?
Page 1 of 5
, Select one: a. .03 b. .13 c. .23 d. .33 e. .43 - Answer: b
The time between incoming customer service calls to a computer-repair hotline follows an
exponential distribution with an expectation of 2 minutes between calls. What is the probability
that the time between calls will be less than 1 minute for a randomly selected period?
Select one: a. .44 b. .31 c. .39 d. .61 e. .07 - Answer: c
The time between customer service calls to a computer-repair hotline follows an exponential
distribution with an expectation of 2 minutes between calls. We collect calls for 40 minutes at
random times during the month (a sample of size n=40). What is the probability that the mean
of our sampling distribution will be greater than 2.2 minutes?
Select one: a. .17 b .26 c. .37 d. .68 e. .78 - Answer: b
Using the value of x from the prior question, what is the standard deviation of x?
Select one: a. 1 b. 3.75 c. 9 d. sqrt(13) e. 1.94 - Answer: e
There was a very short quiz with five questions. The following table shows the number of
correct answers and the cumulative relative frequency for those scores in the class. value: 2 3 4
5 cumulative relative frequency: .13 .55 .925 1 What is the probability that a randomly selected
student from the class scored a 3 on the short quiz?
Select one: a. .13 b. .42 c. .55 d. .375 e. .925 - Answer: b
Use this information for the next three questions. A random variable called L is defined by the
following table, but one of the relative frequencies is missing: value: -5 0 1 3 8 relative
frequency: .17 .11 .23 .15 - Answer:
Page 2 of 5
Ans/ 2025.
You are interested in the number of English-speaking people on the planet who want to play a
new kind of online video game. You asked 300 college students if they were interested in playing
video games, 100 said yes, and of them 20 preferred your game to an existing game that is
widely used. How many people were in the sample?
Select one: a. The number of English-speaking people on the planet who want to play a new
kind of online video game. b. 300 c. 200 d. 100 e. 20 - Answer: b
What is the mean of x? x <- c(12, 14, 11, 14, 13, 15, 12, 16, 10)
Select one: a. 12 b. 13 c. 14 d. 15 e. 16 - Answer: b
The mean weekly sales per employee at a nationwide store is normally distributed with a mean
of $7,300 per week and a standard deviation of $700. What is the probability that a randomly
selected employee will have sales less than $6,500?
Page 1 of 5
, Select one: a. .03 b. .13 c. .23 d. .33 e. .43 - Answer: b
The time between incoming customer service calls to a computer-repair hotline follows an
exponential distribution with an expectation of 2 minutes between calls. What is the probability
that the time between calls will be less than 1 minute for a randomly selected period?
Select one: a. .44 b. .31 c. .39 d. .61 e. .07 - Answer: c
The time between customer service calls to a computer-repair hotline follows an exponential
distribution with an expectation of 2 minutes between calls. We collect calls for 40 minutes at
random times during the month (a sample of size n=40). What is the probability that the mean
of our sampling distribution will be greater than 2.2 minutes?
Select one: a. .17 b .26 c. .37 d. .68 e. .78 - Answer: b
Using the value of x from the prior question, what is the standard deviation of x?
Select one: a. 1 b. 3.75 c. 9 d. sqrt(13) e. 1.94 - Answer: e
There was a very short quiz with five questions. The following table shows the number of
correct answers and the cumulative relative frequency for those scores in the class. value: 2 3 4
5 cumulative relative frequency: .13 .55 .925 1 What is the probability that a randomly selected
student from the class scored a 3 on the short quiz?
Select one: a. .13 b. .42 c. .55 d. .375 e. .925 - Answer: b
Use this information for the next three questions. A random variable called L is defined by the
following table, but one of the relative frequencies is missing: value: -5 0 1 3 8 relative
frequency: .17 .11 .23 .15 - Answer:
Page 2 of 5
