Math 221A Final exam 2023 with complete solution
Which of the following variables is/are quantitative? (Mark all that apply)
a)The number of people in a randomly selected classroom on campus
b)The 3 most common brands of car found in the US
c)The telephone number of a randomly selected business in town
a)The number of people in a randomly selected classroom on campus.
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
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
Systematic Random Sampling
Is the study described in the previous question an experiment or an observational
study, and why?
a) An experiment, because the students had control over which sampling method
they used
b) An experiment, because the students had control over which cereals would be
selected for the study
c) An observational study, because the students had no control over the price of
the individual cereals
, d) An observational study, because the students had no control over which
cereals were selected
c
Which one of the following is a statistically valid reason for sampling randomly
when choosing subjects for a study?
a) Sampling randomly tends to reduce sampling bias or risk
b) Sampling randomly (with a large sample) gives a perfect reflection of the
population
c) Sampling randomly is easier than sampling nonrandomly
d) Actually, there is no statistically valid reason for sampling randomly
a
Which of the following studies depicts an observational study?
a) A parent group examines 25 recently released PG-13 movies and records the
number of sexual innuendos and curse words that occur in each.
b) 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-month intervals over the next year.
a
Say that you are a researcher for a large pharmaceutical company that has
produced a new drug that is believed to help reduce the risk of developing
arthritis. You test the drug and compare it to a placebo by randomly choosing
one group of men and women in their 50's to take the drug and one group of men
and women in their 50's to take a placebo. Each participant takes the drug or
placebo for a period of 10 years, after which the effects of the drug are measured
against the effects of the placebo. What (or who) are the experimental units or
subject?
a) All men and women in their 50's
b) The men and women who took the drug or placebo
c) The researchers
d) The drug and placebo
b
Say that you are a researcher for a large pharmaceutical company that has
produced a new drug that is believed to help reduce the risk of developing
arthritis. You test the drug and compare it to a placebo by randomly choosing
one group of men and women in their 50's to take the drug and one group of men
and women in their 50's to take a placebo. Each participant takes the drug or
Which of the following variables is/are quantitative? (Mark all that apply)
a)The number of people in a randomly selected classroom on campus
b)The 3 most common brands of car found in the US
c)The telephone number of a randomly selected business in town
a)The number of people in a randomly selected classroom on campus.
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
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
Systematic Random Sampling
Is the study described in the previous question an experiment or an observational
study, and why?
a) An experiment, because the students had control over which sampling method
they used
b) An experiment, because the students had control over which cereals would be
selected for the study
c) An observational study, because the students had no control over the price of
the individual cereals
, d) An observational study, because the students had no control over which
cereals were selected
c
Which one of the following is a statistically valid reason for sampling randomly
when choosing subjects for a study?
a) Sampling randomly tends to reduce sampling bias or risk
b) Sampling randomly (with a large sample) gives a perfect reflection of the
population
c) Sampling randomly is easier than sampling nonrandomly
d) Actually, there is no statistically valid reason for sampling randomly
a
Which of the following studies depicts an observational study?
a) A parent group examines 25 recently released PG-13 movies and records the
number of sexual innuendos and curse words that occur in each.
b) 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-month intervals over the next year.
a
Say that you are a researcher for a large pharmaceutical company that has
produced a new drug that is believed to help reduce the risk of developing
arthritis. You test the drug and compare it to a placebo by randomly choosing
one group of men and women in their 50's to take the drug and one group of men
and women in their 50's to take a placebo. Each participant takes the drug or
placebo for a period of 10 years, after which the effects of the drug are measured
against the effects of the placebo. What (or who) are the experimental units or
subject?
a) All men and women in their 50's
b) The men and women who took the drug or placebo
c) The researchers
d) The drug and placebo
b
Say that you are a researcher for a large pharmaceutical company that has
produced a new drug that is believed to help reduce the risk of developing
arthritis. You test the drug and compare it to a placebo by randomly choosing
one group of men and women in their 50's to take the drug and one group of men
and women in their 50's to take a placebo. Each participant takes the drug or
