MAT 131 Unit 3 Exam Questions with Verified
Correct Answer
An urn contains 2 red and 2 green marbles. We pick a marble, record its color, and replace
it. We repeat this procedure a second and a third time. The probability distribution for the
number of red marbles is given below.
Number of red marbles: 0, 1, 2, 3
Probability: 1/8, 3/8, 3/8, 1/8
For this distribution, the probability of 2 or more red marbles is given by:
1/2
Score
100/100
Surveys, if not done correctly, can lead to seriously biased samples. Which of the following
is not a bias due to the sampling plan?
bias due to nonresponse
In order to investigate treatments for morbid obesity, obese subjects satisfying fairly strict
requirements were randomly assigned to one of three treatment groups: (1) gastric bypass
surgery, (2) participation in a diet and exercise program, or (3) both gastric bypass surgery
and participation in a diet and exercise program. Researchers observed the amount of
weight lost five years after the study began. The explanatory variable is:
, the kind of program to which a subject was assigned.
Each month, the census bureau mails survey forms to 250,000 households asking questions
about the people living in the household and about such things as motor vehicles and
housing costs. Telephone calls are made to households that don't return the form. In one
month, responses were obtained from 240,000 of the households contacted. The sample is:
the 240,000 households that responded.
A group of veterinarians at a major veterinary hospital was interested in investigating a
possible link between enteroliths (stones that form in the colon of horses) and diet. They
decided to conduct a survey of the feeding practices for horses in the hospital's state. They
created a survey questionnaire and decided to administer it to the owners of every fifth
horse being treated at the hospital. The sample is:
a convenience sample
A North American roulette wheel has 38 slots, of which 18 are red, 18 are black, and 2 are
green. If you bet on red, the probability of winning is 18/38 = 0.4737. The probability
0.4737 represents:
the proportion of times this event will occur in a very long series of individual bets on red.
To investigate whether women are more likely than men to prefer Democratic candidates, a
political scientist selects a large sample of registered voters, both men and women. She asks
every voter whether they voted for the Republican or the Democratic candidate in the last
election. This is:
an observational study
Correct Answer
An urn contains 2 red and 2 green marbles. We pick a marble, record its color, and replace
it. We repeat this procedure a second and a third time. The probability distribution for the
number of red marbles is given below.
Number of red marbles: 0, 1, 2, 3
Probability: 1/8, 3/8, 3/8, 1/8
For this distribution, the probability of 2 or more red marbles is given by:
1/2
Score
100/100
Surveys, if not done correctly, can lead to seriously biased samples. Which of the following
is not a bias due to the sampling plan?
bias due to nonresponse
In order to investigate treatments for morbid obesity, obese subjects satisfying fairly strict
requirements were randomly assigned to one of three treatment groups: (1) gastric bypass
surgery, (2) participation in a diet and exercise program, or (3) both gastric bypass surgery
and participation in a diet and exercise program. Researchers observed the amount of
weight lost five years after the study began. The explanatory variable is:
, the kind of program to which a subject was assigned.
Each month, the census bureau mails survey forms to 250,000 households asking questions
about the people living in the household and about such things as motor vehicles and
housing costs. Telephone calls are made to households that don't return the form. In one
month, responses were obtained from 240,000 of the households contacted. The sample is:
the 240,000 households that responded.
A group of veterinarians at a major veterinary hospital was interested in investigating a
possible link between enteroliths (stones that form in the colon of horses) and diet. They
decided to conduct a survey of the feeding practices for horses in the hospital's state. They
created a survey questionnaire and decided to administer it to the owners of every fifth
horse being treated at the hospital. The sample is:
a convenience sample
A North American roulette wheel has 38 slots, of which 18 are red, 18 are black, and 2 are
green. If you bet on red, the probability of winning is 18/38 = 0.4737. The probability
0.4737 represents:
the proportion of times this event will occur in a very long series of individual bets on red.
To investigate whether women are more likely than men to prefer Democratic candidates, a
political scientist selects a large sample of registered voters, both men and women. She asks
every voter whether they voted for the Republican or the Democratic candidate in the last
election. This is:
an observational study
