STAT 217 exam 2 Questions with Correct Answers (Grade A+)
Question 1: Researchers want to know if there is a relationship between color of car (white, red, blue,
other) and if a speeding ticket is issued or if the person is released with a warning. To test this
researchers monitored a known speed trap (the police officers did not know they were being
monitored). If a person was pulled over for speeding, the color of the car was recorded and if they were
issued a speeding ticket (or not). What is the correct null hypothesis for the Chi-Squared Test of
Independence? (Select all of the correct answers.)
a. The population distribution of if a speeding ticket was issued or not was the same across all colors of cars
that people speeding drove.
b. There is no correlation between the color of a car and if a person was issued a speeding ticket or not.
c. There is no relationship between the the color of the car that a person speeding drove and if they were issued
a speeding ticket.
d. The color of the car that a person speeding drove and if they were issued a speeding ticket are independent.
Answer: C. There is no relationship between the the color of the car that a person speeding drove and if they
were issued a speeding ticket. AND d. The color of the car that a person speeding drove and if they were
issued a speeding ticket are independent.
Question 2: What is the correct alternative hypothesis for the Chi-Squared Test of Independence?
(Select all of the correct answers.)
a. The color of the car that a person speeding drove and if they were issued a speeding ticket are not
independent.
b. The population distribution of if a speeding ticket was issued or not was not the same across all colors of cars
that people speeding drove.
c. There is a correlation between the color of a car and if a person was issued a speeding ticket or not.
d. There is a relationship between the the color of the car that a person speeding drove and if they were issued a
speeding ticket.
Answer: A. The color of the car that a person speeding drove and if they were issued a speeding ticket are
not independent. AND d. There is a relationship between the the color of the car that a person speeding
drove and if they were issued a speeding ticket.
Page 1
, Question 3: Research veterinarians are concerned that the diets dogs eat contributes to heart failure.
Vets believed that canine dilated cardiomyopathy (DCM) in dogs can be caused by eating certain pet
foods containing peas, lentils, other legume seeds, or potatoes as main ingredients. These reports are
unusual because DCM is occurring in breeds not typically genetically prone to the disease. Three diets
were considered, diets with grain as a main ingredient, diets that are considered "grain-free", and raw
diets. (This is example is based off of the study found here:
https://www.fda.gov/AnimalVeterinary/NewsEvents/CVMUpdates/ucm613305.htm). Owners who fed
their dogs each of these diets for at least a year were recruited (30 for each diet) and monitored until the
dog's death. Vets watched for canine dilated cardiomyopathy (DCM) in these dogs; DCM/No DCM was
recorded after death. What is the correct null hypothesis for this Chi-Squared Test of Homogeneity
situation? (Select all that apply.)
a. There is no relationship between the diet a dog is fed and if they had canine dilated cardiomyopathy (DCM).
b. The diet a dog is fed and if they had canine dilated cardiomyopathy (DCM) are independent.
c. The proportion of dogs that had canine dilated cardiomyopathy (DCM) were the same for each diet that they
were fed.
d. There was no correlation between the diet a dog was fed and if they had canine dilated cardiomyopathy
(DCM).
Answer: ONLY c. The proportion of dogs that had canine dilated cardiomyopathy (DCM) were the same
for each diet that they were fed.
Question 4: What is the correct alternative hypothesis for this Chi-Squared Test of Homogeneity
situation? (Select all that apply.)
a. There is a relationship between the diet a dog is fed and if they had canine dilated cardiomyopathy (DCM).
b. The diet a dog is fed and if they had canine dilated cardiomyopathy (DCM) are not independent.
c. The proportion of dogs that had canine dilated cardiomyopathy (DCM) were not the same for each diet that
they were fed.
d. There was a correlation between the diet a dog was fed and if they had canine dilated cardiomyopathy
(DCM).
Answer: ONLY c. The proportion of dogs that had canine dilated cardiomyopathy (DCM) were not the
same for each diet that they were fed.
Question 5: The cheating data set explores student behavior. A survey of 319 randomly selected
undergraduate students at a university were asked whether they had ever lied to avoid taking an exam
or a paper or both and if they had copied on exams, papers or both. Theresults with either exam or
paper collapsed into one level are summarized below in a contingency table. liar2 none examorpaper
copy both none 207 53 5 eorp 23 9 4 lieboth 11 5 2 Which type of test and which type of plot should be
used?
a. Homogeneity; mosaic plot
b. Independence; stacked bar chart
c. Independence; mosaic plot
d. Homogeneity; stacked bar chart
Answer: C. Independence; mosaic plot
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Question 1: Researchers want to know if there is a relationship between color of car (white, red, blue,
other) and if a speeding ticket is issued or if the person is released with a warning. To test this
researchers monitored a known speed trap (the police officers did not know they were being
monitored). If a person was pulled over for speeding, the color of the car was recorded and if they were
issued a speeding ticket (or not). What is the correct null hypothesis for the Chi-Squared Test of
Independence? (Select all of the correct answers.)
a. The population distribution of if a speeding ticket was issued or not was the same across all colors of cars
that people speeding drove.
b. There is no correlation between the color of a car and if a person was issued a speeding ticket or not.
c. There is no relationship between the the color of the car that a person speeding drove and if they were issued
a speeding ticket.
d. The color of the car that a person speeding drove and if they were issued a speeding ticket are independent.
Answer: C. There is no relationship between the the color of the car that a person speeding drove and if they
were issued a speeding ticket. AND d. The color of the car that a person speeding drove and if they were
issued a speeding ticket are independent.
Question 2: What is the correct alternative hypothesis for the Chi-Squared Test of Independence?
(Select all of the correct answers.)
a. The color of the car that a person speeding drove and if they were issued a speeding ticket are not
independent.
b. The population distribution of if a speeding ticket was issued or not was not the same across all colors of cars
that people speeding drove.
c. There is a correlation between the color of a car and if a person was issued a speeding ticket or not.
d. There is a relationship between the the color of the car that a person speeding drove and if they were issued a
speeding ticket.
Answer: A. The color of the car that a person speeding drove and if they were issued a speeding ticket are
not independent. AND d. There is a relationship between the the color of the car that a person speeding
drove and if they were issued a speeding ticket.
Page 1
, Question 3: Research veterinarians are concerned that the diets dogs eat contributes to heart failure.
Vets believed that canine dilated cardiomyopathy (DCM) in dogs can be caused by eating certain pet
foods containing peas, lentils, other legume seeds, or potatoes as main ingredients. These reports are
unusual because DCM is occurring in breeds not typically genetically prone to the disease. Three diets
were considered, diets with grain as a main ingredient, diets that are considered "grain-free", and raw
diets. (This is example is based off of the study found here:
https://www.fda.gov/AnimalVeterinary/NewsEvents/CVMUpdates/ucm613305.htm). Owners who fed
their dogs each of these diets for at least a year were recruited (30 for each diet) and monitored until the
dog's death. Vets watched for canine dilated cardiomyopathy (DCM) in these dogs; DCM/No DCM was
recorded after death. What is the correct null hypothesis for this Chi-Squared Test of Homogeneity
situation? (Select all that apply.)
a. There is no relationship between the diet a dog is fed and if they had canine dilated cardiomyopathy (DCM).
b. The diet a dog is fed and if they had canine dilated cardiomyopathy (DCM) are independent.
c. The proportion of dogs that had canine dilated cardiomyopathy (DCM) were the same for each diet that they
were fed.
d. There was no correlation between the diet a dog was fed and if they had canine dilated cardiomyopathy
(DCM).
Answer: ONLY c. The proportion of dogs that had canine dilated cardiomyopathy (DCM) were the same
for each diet that they were fed.
Question 4: What is the correct alternative hypothesis for this Chi-Squared Test of Homogeneity
situation? (Select all that apply.)
a. There is a relationship between the diet a dog is fed and if they had canine dilated cardiomyopathy (DCM).
b. The diet a dog is fed and if they had canine dilated cardiomyopathy (DCM) are not independent.
c. The proportion of dogs that had canine dilated cardiomyopathy (DCM) were not the same for each diet that
they were fed.
d. There was a correlation between the diet a dog was fed and if they had canine dilated cardiomyopathy
(DCM).
Answer: ONLY c. The proportion of dogs that had canine dilated cardiomyopathy (DCM) were not the
same for each diet that they were fed.
Question 5: The cheating data set explores student behavior. A survey of 319 randomly selected
undergraduate students at a university were asked whether they had ever lied to avoid taking an exam
or a paper or both and if they had copied on exams, papers or both. Theresults with either exam or
paper collapsed into one level are summarized below in a contingency table. liar2 none examorpaper
copy both none 207 53 5 eorp 23 9 4 lieboth 11 5 2 Which type of test and which type of plot should be
used?
a. Homogeneity; mosaic plot
b. Independence; stacked bar chart
c. Independence; mosaic plot
d. Homogeneity; stacked bar chart
Answer: C. Independence; mosaic plot
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