Exam 1 Review biostats questions with
complete solutions
Which of the following variables is/are quantitative? (Mark all that apply)
The number of people in a randomly selected classroom on campus
The 3 most common brands of car found in the US
The telephone number of a randomly selected business in town - correct answer ✔✔The number of
people in a randomly selected classroom on campus
Which one of the following is a statistically valid reason for sampling randomly when choosing subjects
for a study?
Correct Response
Sampling randomly tends to reduce sampling bias or risk
Sampling randomly (with a large sample) gives a perfect reflection of the population
Sampling randomly is easier than sampling nonrandomly
Actually, there is no statistically valid reason for sampling randomly - correct answer ✔✔Sampling
randomly tends to reduce sampling bias or risk
,A study conducted by researchers from the Department of Education wanted to know the average debt
of college students in the United States. In order to obtain a sample representative of all students, the
researchers divided college students into the four classes (freshman, sophomore, junior, and senior) and
then took a random sample of students from each class. Which sampling method did they use?
Stratified random sampling
Systematic random sampling
Cluster sampling
Simple random sampling - correct answer ✔✔Stratified random sampling
Students in an Introductory Statistics class at BYU-Idaho were studying prices of cold cereal at grocery
stores in Rexburg. To get a sample of cold cereal prices, they went to Albertson's and rolled a die to
decide which box from the left of the top shelf they would start on. They then recorded every 6th cereal
after the first, moving from left to right down the shelves, recording the name, size, and price of each
cereal in their sample. Which sampling method did they use?
Stratified random sampling
Systematic random sampling
, Cluster sampling
Simple random sampling - correct answer ✔✔Systematic random sampling
Is the study described in the previous question an experiment or an observational study, and why?
An experiment, because the students had control over which sampling method they used
An experiment, because the students had control over which cereals would be selected for the study
An observational study, because the students had no control over the price of the individual cereals
An observational study, because the students had no control over which cereals were selected - correct
answer ✔✔An observational study, because the students had no control over the price of the individual
cereals
Which of the following studies depicts an observational study?
A parent group examines 25 recently released PG-13 movies and records the number of sexual
innuendos and curse words that occur in each.
A sample of 504 patients in early stages of Alzheimer's disease is divided into two groups. One group
receives an experimental drug and the other a placebo. The advance of the disease is tracked at one-
complete solutions
Which of the following variables is/are quantitative? (Mark all that apply)
The number of people in a randomly selected classroom on campus
The 3 most common brands of car found in the US
The telephone number of a randomly selected business in town - correct answer ✔✔The number of
people in a randomly selected classroom on campus
Which one of the following is a statistically valid reason for sampling randomly when choosing subjects
for a study?
Correct Response
Sampling randomly tends to reduce sampling bias or risk
Sampling randomly (with a large sample) gives a perfect reflection of the population
Sampling randomly is easier than sampling nonrandomly
Actually, there is no statistically valid reason for sampling randomly - correct answer ✔✔Sampling
randomly tends to reduce sampling bias or risk
,A study conducted by researchers from the Department of Education wanted to know the average debt
of college students in the United States. In order to obtain a sample representative of all students, the
researchers divided college students into the four classes (freshman, sophomore, junior, and senior) and
then took a random sample of students from each class. Which sampling method did they use?
Stratified random sampling
Systematic random sampling
Cluster sampling
Simple random sampling - correct answer ✔✔Stratified random sampling
Students in an Introductory Statistics class at BYU-Idaho were studying prices of cold cereal at grocery
stores in Rexburg. To get a sample of cold cereal prices, they went to Albertson's and rolled a die to
decide which box from the left of the top shelf they would start on. They then recorded every 6th cereal
after the first, moving from left to right down the shelves, recording the name, size, and price of each
cereal in their sample. Which sampling method did they use?
Stratified random sampling
Systematic random sampling
, Cluster sampling
Simple random sampling - correct answer ✔✔Systematic random sampling
Is the study described in the previous question an experiment or an observational study, and why?
An experiment, because the students had control over which sampling method they used
An experiment, because the students had control over which cereals would be selected for the study
An observational study, because the students had no control over the price of the individual cereals
An observational study, because the students had no control over which cereals were selected - correct
answer ✔✔An observational study, because the students had no control over the price of the individual
cereals
Which of the following studies depicts an observational study?
A parent group examines 25 recently released PG-13 movies and records the number of sexual
innuendos and curse words that occur in each.
A sample of 504 patients in early stages of Alzheimer's disease is divided into two groups. One group
receives an experimental drug and the other a placebo. The advance of the disease is tracked at one-
