Compare a science experiment fairly
Find the changed condition, measured result, and evidence limit.
Change one thing at a time
The independent variable is the condition changed. The dependent variable is the measured result.
Original practice experiment: Two groups of the same seedlings get the same soil, water, and temperature. Group A gets 4 hours of light daily; Group B gets 8. After 14 days, average heights are 6 cm and 9 cm.
Say only what the data support
The changed condition is hours of light. The measured result is average height after 14 days. Group B is 3 cm taller on average.
This supports greater growth with 8 hours under these conditions. It does not show what happens with 12 hours or with every plant species. More seedlings and repeated trials would strengthen the evidence.
Your turn.
Try each question before opening the explanation. These are FinishHigh practice examples, not GED® test questions.
What is the independent variable?
Show the answer and why
Hours of light each day.
Why give both groups the same water?
Show the answer and why
So a difference in water is not another explanation for the result.
How much taller is Group B on average?
Show the answer and why
3 cm: 9 − 6 = 3.
Can we conclude 12 hours works best?
Show the answer and why
No. Twelve hours was not tested.
Trusted sources and further study
Sources guide the topics and factual information. The lesson wording, examples, and questions are original FinishHigh material.
- Science study booklet ↗GED Testing Service · checked 2026-10-07
- Get Sum Math practice ↗Get Sum Math · checked 2026-10-07
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