At least five.
As many as you can find that would effect your experiment in some way.
as much data as possible can be colleced in the time availble
to gather data from data to create an controlled experiment
to gather data from data to create an controlled experiment
baecuse so you can have a greater apertunity on getting your anwser
What a stupid question. Because you should.
At least five.
They shouldn't, ever. It defies the whole point of a controlled experiment.
As few as possible.
There is no set number, the number is dictated by the design of the experiment.
As many as you can find that would effect your experiment in some way.
as much data as possible can be colleced in the time availble
A experiment should only have one variable.
to gather data from data to create an controlled experiment
to gather data from data to create an controlled experiment
to gather data from data to create an controlled experiment