Sampling
What type of sampling uses subjects that are readily and easily available?
What is a Convenience Sampling?
The variable that is being affected and that the researchers are measuring
What is Response Variable
Observes individuals and measures variables of interest but does not attempt to influence the responses
What is an Observational Study?
What do you need in order to generalize results to a population
Random Sampling
What is Mr. Purvis's favorite board game?
Chess
A sample obtained by choosing a random starting point then sampling every nth subject
What is a Systematic Sample?
The variable that the experimenters are manipulating and will affect the response Variable
What is the explanatory variable
Deliberately imposes some treatment on individuals to measure their response.
What is an Experiment?
What do you need in order to conclude causation in an experiment
Random Assignment
Where did Mr. Purvis go to College?
Amherst College (minus points if you say UMASS Amherst)
Mr. Purvis assigns everybody a different number then uses a random number generator to tell him who to use in his sample
Simple Random Sample (SRS)?
What is a treatment that has no affect but the subject may believe that it does, thus changing the outcome
What is a placebo?
A medical team examines the records of 5 large hospitals and compares the survival times of those cancer patients who had surgery versus those who had chemotherapy.
Observational Study
I randomly sample Seniors from BCCS about their favorite sport. Can I generalize the results to the entire school?
No, because it was not a random sample of the entire school
Mr. Purvis double majored in college. What were these two majors?
Statistics and Music (no points if you said math)
Divide the population into boys and girls then select a random sample within each group.
What is a Stratified Random Sampling?
What the results of a study are off from the truth this is often because of some type of
Bias or confounding variable
In gym class, the effect of exercise on blood pressure is studied by requiring that half of the students walk a mile each day while the other students run a mile each day,
Experiment
In an experiment to see if a SAT prep class affects SAT grades, I let students choose if they wanted to be in the class or not. I saw that the SAT prep class got higher scores overall. Can I conclude that the prep class causes higher scores
No, because the treatments were not randomly assigned
What sport did Mr. Purvis play in College?
Rugby
Divide the class into table groups then randomly choose a few of those groups. Every member in those group gets sampled.
What is a Cluster Sample?
The group that does not receive the treatment is called the
Control group
The relationship between weights of bears and their lengths is studied by measuring bears that have been anesthetized
Observational Study
What conclusion can I make from the following Experiment?
50 NBA players are chosen randomly to be in this study. 25 are randomly assigned to wear Jordans in their next game and 25 are randomly assigned to wear LeBrons. The player wearing Jordans overall scored higher than the LeBron group.
Among all NBA players, wearing Jordans causes players to get more points than LeBrons
What month did Mr. Purvis get married in?
April