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.
A study in which results are measured without intervention from the researcher is called... -
Answer: Observational study.
Which of the following best classifies the arrangement of bean bags? - Answer: Low accuracy
and low precision.
Page 1 of 7
, 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.
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.
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.
A study in which results are measured without intervention from the researcher is called... -
Answer: Observational study.
Which of the following best classifies the arrangement of bean bags? - Answer: Low accuracy
and low precision.
Page 1 of 7
, 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.
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.
Page 2 of 7
