SAMPLE SIZE
An important part of science is that it is reproducible.
That is, if someone else does an experiment the same way, they should get
the same results. This way, you can be confident in your conclusions and
others are more likely to believe you. To make sure that will happen you
should do your experiment more than once, use several plants or animals
or sizes or thicknesses or whatever! In our "How does changing the
pH of water effect plant growth" project, we would want to use as many
plants as we could. We also would want to keep several in our control group
and have several for each of the different pH values we were testing. We
might also use more than just one type of plant or more than one type of
soil. If you use more than one manipulated variable, be sure to have a control
sample for each one.
How would you set up your sample for these projects?
What kind of car window tinting is best?
Where is the coolest part of the house?
What type of food do cockroaches prefer?