ST 311 Final Exam 2026/2027

ST 311 Final Exam
A researcher was interested in utilities provided by city governments. The researcher
randomly selected 20 counties from a list of all counties in the U.S. From each of these
counties the researcher then contacted each city in those counties (a total of 192) and
found that 12 (6.25%) of them provided electricity to their residents.
Which of the following are true?
Select all that apply.
-The population of interest is all city governments in the U.S.
-The population of interest is the 192 cities.
-The population of interest is all city governments that provide utilities to their residents.
-The population of interest is 6.25%.
-The parameter of interest is the proportion of the city governments in the U.S. that
provide electricity to their residents.
-The parameter of interest is 6.25%.
-The population of interest is the 20 counties.
-The parameter of interest is the list of all counties in the U.S.
A researcher was interested in utilities provided by city governments. The researcher
randomly selected 20 counties from a list of all counties in the U.S. From each of these
counties the researcher then contacted each city government (a total of 192) and found
that 12 (6.25%) of them provided electricity to their residents. The type of sample used
in this example is a
-simple random sample.
-cluster random sample.
-stratified random sample.
-none of the above.
A professor wanted to determine the proportion of students in his class who have
cheated on an exam. The professor selects a random sample of 30 students from his
class and emails them the question "Have you ever cheated on an exam?". He receives
responses from 10 of the 30 students. Which of the following statements are true?
Select all that apply.
-This study would suffer from undercoverage because the professor should have
selected a sample from the entire student body of the university.
-This study suffers from non-response bias because only 33% of the people surveyed
provided a response.
-This study suffers from response bias since students will not want to tell a professor
whether or not they have cheated.
-The study should not suffer from any bias since it was based on a random sample