SOLUTIONS GRADED A+
◉ In the population of all Olympic freestyle wrestlers, is there a
correlation between weight (in kilograms) and height (in
centimeters)?
Weight (in kilograms) is a ______ variable.
Height (in centimeters) is a _______ variable. Answer: quantitative
◉ A farmer wants to compare the milk production of dairy cattle fed
different types of feed: (1) Purina Mills, (2) Nutrena, and (3)
Modesto. They have 300 cows and randomly assign each cow to eat
one of the three types of feed for a period of 3 months. At the end of
the 3 months, they record the milk production of each cow.
The cases are the_____
The explanatory variable is______
The response variable is______ Answer: cows, type of feed, milk
production
◉ There are more than 14,000 Penn State World Campus students. A
survey was sent to 800 randomly selected World Campus students.
The 800 students who were selected to complete the survey were
the _______ . All Penn State World Campus students are the ________.
Answer: sample, population
,◉ A school psychologist wants to know if there is a relationship
between SAT-Verbal and SAT-Math scores in juniors in her school
district. She has a list of all 1,200 juniors in her district. She uses
statistical software to obtain a list of 20 names from that list. The
statistical software uses a random number generator so that each of
the 1,200 juniors has an equal probability of being selected.
Is this an example of a convenience or simple random sampling
method? Answer: simple random sampling method
◉ A researcher knocks on doors in your neighborhood each
weekday morning between 9 AM and 11 AM for a week to conduct
research on daycare needs for your community. You leave for work
at 7:30 AM each day to drop your kids off at daycare and go to work.
She's knocked on your door two different days and writes "not
home" in her notes.
Which type of bias is present in this researcher's study? Answer:
non-response bias
◉ Decide if this study is experimental or observational.
An educational researcher wanted to compare the quiz scores of
students who received a lecture with the quiz scores of students
who received an active learning-based lesson. Students from one
section of STAT200 were randomly assigned to either the lecture
condition or the active learning condition. After the lesson all
students took the same quiz. Students who received the active
, learning lesson scored higher than those who received the lecture.
Answer: experimental
◉ Decide if this study is experimental or observational.A group of
college students is doing a project on the relationship between shoe
size and height. They take a sample of 35 students and record each
individual's shoe size and height. They find that there is a strong
relationship between shoe size and height. Answer: observational
◉ Do preschoolers who were breastfed for a least six month have
higher scores on a measure of emergent reading skills than
preschoolers who were never breastfed?
Which of the following may be a confounding variable in this study?
a. mother's education
b. preschoolers
c. emergent reading skill Answer: a
◉ _______refers to randomly selecting participants from the
population.
________ refers to randomly assigning participants to different groups.
Answer: Random sampling, Randomization
◉ Do Penn State freshmen or sophomores tend to weigh more?