Introduction to Statistics Unit 1: Milestone 1/
Answered Exam Questions.
Which of these statements best defines a stratified random sample? - Answer: It is a sample
where the population is first broken into groups and then elements are randomly selected, in
proportion, from each group.
Which of the following data types will be continuous? - Answer: The amount of snow that fell
last night.
Which of the following best classifies the arrangement of bean bags? - Answer: Low accuracy
and low precision.
Mike wants to find out the approximate income for professors in Michigan. He decides to
randomly select 50 professors who work for a college or university in Michigan and obtain their
salaries.
Page 1 of 7
, What are the sample and the population of Mike's study? - Answer: The 50 professors that Mike
interviews are his sample, and all of the professors who work in Michigan are the population.
James conducts a survey to study the relationship between cell phone use and grades earned
during the fall semester. James suspects that there might be a lot of other factors that affect
grades besides cell phones.
Which of the following could be a confounding variable in James's study? - Answer: Time spent
studying.
Cindy measured and recorded the temperature of a liquid for an experiment. She used a poorly
calibrated thermometer and noted the temperature as 100.5 degrees Fahrenheit. The actual
temperature of the liquid was 95 degrees Fahrenheit.
The percent error in her calculation is... - Answer: 5.79%
On a candy production line, 3% of bags are overfilled. An employee randomly selects 100 bags
and finds that 5% are overfilled. A second employee takes another random sample of 250 bags
and finds that 2% are overfilled.
Which of the following explains why there is a difference between the two percentages? -
Answer: Random error; the numbers were different due to variability inherent in sampling.
Rob sent an email survey to 2,000 cell phone owners asking about their satisfaction with their
current plan. Only 256 people returned the survey and they were predominately 18-24 years
old.
Page 2 of 7
Answered Exam Questions.
Which of these statements best defines a stratified random sample? - Answer: It is a sample
where the population is first broken into groups and then elements are randomly selected, in
proportion, from each group.
Which of the following data types will be continuous? - Answer: The amount of snow that fell
last night.
Which of the following best classifies the arrangement of bean bags? - Answer: Low accuracy
and low precision.
Mike wants to find out the approximate income for professors in Michigan. He decides to
randomly select 50 professors who work for a college or university in Michigan and obtain their
salaries.
Page 1 of 7
, What are the sample and the population of Mike's study? - Answer: The 50 professors that Mike
interviews are his sample, and all of the professors who work in Michigan are the population.
James conducts a survey to study the relationship between cell phone use and grades earned
during the fall semester. James suspects that there might be a lot of other factors that affect
grades besides cell phones.
Which of the following could be a confounding variable in James's study? - Answer: Time spent
studying.
Cindy measured and recorded the temperature of a liquid for an experiment. She used a poorly
calibrated thermometer and noted the temperature as 100.5 degrees Fahrenheit. The actual
temperature of the liquid was 95 degrees Fahrenheit.
The percent error in her calculation is... - Answer: 5.79%
On a candy production line, 3% of bags are overfilled. An employee randomly selects 100 bags
and finds that 5% are overfilled. A second employee takes another random sample of 250 bags
and finds that 2% are overfilled.
Which of the following explains why there is a difference between the two percentages? -
Answer: Random error; the numbers were different due to variability inherent in sampling.
Rob sent an email survey to 2,000 cell phone owners asking about their satisfaction with their
current plan. Only 256 people returned the survey and they were predominately 18-24 years
old.
Page 2 of 7
