Variables/Observational units
Studies
Bias/Lurking variables
Sampling
Experimental Design
100
A veterinarian is going to investigate whether homes with more pets tend to have more fleas. In this scenario, the explanatory variable is _______ and the response variable is ________.
Number of pets; number of fleas spotted in a period of time
100
What would you expect to be the correlation between house size (in square feet) and electricity bill
Positively correlated
100
Dr. Peterson went to Chestnutwold Elementary School and found that the taller students tended to read at a high level. Provide at least one lurking variable that may explain this correlation.
(answers vary)
100
True or False: Putting names in a hat and pulling ten out is an example of a simple random sample
True
100
True or False: A blind experiment is when only the control group is unaware they are the control group
False
200
If food items are the observation units, what kind of variable is "sold at Acme"
Categorical; nominal
200
Which of the following pairs of variables would you expect to be independent of one another
Height; shoe size
Hours of sleep; hair color
The average number of TVs per home; life expectancy
Lighter in pocket; cancer
Hours of sleep; hair color
200
What type of evidence is best for showing causality
Experimental
Observational
Anecdotal
Whatever Mr. Rau says
Experimental
200
Mark surveyed 200 Haverford students and asked them if they pack their lunches or buy them at the school. 50 people responded and said they bought their lunch at school. What is the statistic?
25% of the students in the sample buy lunch at school
200
True or False: The placebo effect is when a patient takes a fake or inactive drug thinking it is real and experiences symptoms/recovery similar to a real drug
True
300
A researcher is looking for a link between people who eat out once a week and happiness. They claim that people who eat out at least once a week are happier than people who do not. In order to test this, they survey 100 people about their eating out habits and happiness on a scale of 1-10 (1 is most sad, 10 is most happy). What are the observational units?
Each individual person
300
True or False: When done properly, observation studies can show causality.
False
300
Briana conducts an observational study comparing the number of hours spent exercising a week and weekly income. She noticed that people who spend more hours exercising a week had a smaller weekly income. Which response(s) point to a potential confounding variable.
Hours spend working
number of siblings
Amount of free time per week
size of home
Hours spend working
Amount of free time per week
300
Which of the following is true about parameters in statistics
They are characteristics of a population
They cannot be approximated by collecting a nonbiased sample
Only play a role in observation studies
Is always 0 when the response variable is numeric
They are characteristics of a population
300
For which of the following would it be reasonable to conduct an experimental study. Check all that apply.
Does doing 100 push-ups every day increase GPA?
Does darker hair affect eyesight?
Does household income affect the number of people living in the household?
Does Tamiflu decrease flu symptoms?
Does doing 100 push-ups every day increase GPA?
Does Tamiflu decrease flu symptoms?
400
If high schools are the observation units, what kind of variable is "the size of the student body"
Numerical; discrete
400
Match the research method with its proper category (Anecdotal, Observation, Experimental) when trying to determine if playing video games every day makes you smarter
My friend who plays a lot of video games every day is doing really well in school
I surveyed 50 people at my school and the average GPA of video game players is .5 higher than the average not video game player
I randomly selected 30 people from my school. I told 15 of them to play video games for an hour each day and told the other 15 not to play at all. The ones that played every day did better by .75 on average
Anecdotal, Observation, Experimental
400
Scientists are interested in the relationship between carbon dioxide emissions and global warming. They look at the emission of the countries in the UN from 1970 to the present day. They noticed that as carbon dioxide emission increased the average global temperature increased as well. Some scientists claim that this study is proof that carbon dioxide emissions are causing global warming. Although this may be the case, provide at least two reasons why this study does not prove carbon dioxide emissions increase global warming.
(answers vary)
400
Match each example with its sampling method
Mr. Rau splits up the class into groups by favorite subject and polls all the students who like English and Math the most.
To learn about culture at Haverford, Kim interviews 3 players from each sports team
To call on a student, Mr. Rau uses popsicle sticks with his eyes closed
To judge the effectiveness of Verizon customer service, a researcher interviews every 5th account on a list of Verizon accounts
Cluster, stratified, simple random, systematic
400
What are the three principles of experimental design that every proper experiment needs
Replication, random, control
500
In a study where restaurants are the observation units which of the following is not a variable:
Most popular menu item
Average number of customers in a day
Yearly revenue
Number of restaurants
Number of restaurants
500
Julius surveys all math teachers at Haverford high school. He asks each teacher how much homework they assign on a nightly basis, the average grade in the class, the distribution of males and females, and the number of students they have in total. What combination of explanatory and response variables makes the most sense (i.e. most likely to have a correlation)?
Explanatory: how much homework; Response: average grade in the class
Explanatory: how much homework; Response: distribution of males and females
Explanatory: distribution of males and females; Response: total number of students
Explanatory: average grade in the glass; Response: number of total students
Explanatory: how much homework; Response: average grade in the class
500
In the image above from the Jelly Blubbers activity, what sampling method shows the smallest bias and variability? Explain.
(Answers vary)
500
If the larger circle in the image above represents the population and the smaller circle represents a sample, what does the box represent, and is the sample roughly representative of the population?
Sample frame and yes
500
What is "blocking" in an experimental study?
Splitting the test subjects into groups and conducting the experiment in each group