Question

which is an example of an experiment?
a. interviewing college students to find what percentage expect a job immediately after graduation
b. collecting the cholesterol readings of a group of elderly people in a small town
c. calling a sample of registered voters before an election to find out what issues concern them most
d. testing the effectiveness of a new hair product by allowing one group to use it and comparing results against a group that doesnt use it

Explanation:

An experiment involves manipulating a variable (here, using the new hair product) and comparing groups (one using the product, one not) to observe the effect. Options A, B, C are surveys/observations without manipulation. Option D has a treatment group (uses product) and control group (doesn't), fitting an experiment.

Answer:

D. Testing the effectiveness of a new hair product by allowing one group to use it and comparing results against a group that doesn't use it