Question

A sample that is treated exactly like the other experimental groups except that the variable is not applied to it is a(n) _____.

a. observation
b. variable
c. control
d. hypothesis

Answer 1

This is a "control" - answer c).

You always need a control in an experiment, otherwise you don't know what influenced the changes. Imagine you make children eat more vegetables and they grow - do you know if it's due to vegetables or not? You need to have another group that eats normal amounts of vegetables to compare this.