1. AP Statistics Section 4.3 By Suji Balfe, Julie Baldauf & Matthew Carey
Using Studies Wisely
AP Statistics Section 4.3
By Suji Balfe, Julie Baldauf & Matthew Carey

2. Scope of Inference
Random selection of individuals allows inference about the population.
Random assignment of individuals to groups allows inference about cause and effect.

3. The Challenges of Establishing Causation
A lack of realism about the treatments, subjects, or environment of an experiment can limit the ability to apply the conclusions of an experiment to a larger setting.
Sometimes it isn’t practical or ethical to do an experiment. In these cases, it is still sometimes possible to build a strong case for causation.

4. Criteria for Establishing Causation
The association is strong.
The association is consistent.
Larger values of the explanatory variable are associated with stronger responses.
The alleged cause precedes the effect in time.
The alleged cause is plausible.

5. Data Ethics
The most common rule of thumb is, “Don’t harm anyone in the process of the experiment”
Rules Include:
Planned Studies must be reviewed by an Institutional Review Board
the Board judges whether the study will obtain useful information or if it is statistically correct,
It also evaluates whether the safety of those involved in the study is ensured or not

6. Data Ethics (cont.) Informed Consent by subjects must be obtained
Subjects must know the complete implications of their participation, how the study will be conducted, and the purpose of the study
Consent is usually given in written form
Confidentiality with subjects is non-negotiable; the experiment must be confidential
Protects the privacy of the participants
Not the same as anonymity, where the individuals in the study are unknown to everyone, including the researchers

7. Be Smart About it
Certain experiments are OBVIOUSLY not safe ones, and should not be carried through with
Some bad sample designs:
How many average bee stings does a subject receive when the subject sticks his/her arm in a box of bees?
What is the average duration of burning on a subject’s skin when hot water is poured over it?
If you, the interviewer would not participate in the study, it is likely that the study is dangerous and no one else will participate either

8. Study Tips Read the question carefully
Use your common sense and do not overread into the question to much
if the experiment sounds iffy, chances are it is
Ask yourself if you would be comfortable participating in the experiment yourself

9. IRB Video