Why your tutor wrote "It's Not An Experiment" on your essay
Wednesday, 11 Dec 2019, 14:21
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Edited by Melanie Rimmer, Wednesday, 11 Dec 2019, 14:30
An experiment
is a special type of study. It's the only kind of study that can demonstrate a cause-effect relationship. In an experiment:
The researcher is trying to test a cause-effect hypothesis,
e.g. does lemonade make plants grow faster?
There are (at least) two groups (two identical groups of plants)
One is
a control group (the group
that gets watered with water)
One (or more) is an experimental group (the group that gets watered with lemonade)
There is an independent variable, which is the
thing hypothesised to have an effect (the lemonade)
The researcher controls which group gets the independent variable and which group doesn't
There is a dependent variable, which is the
thing hypothesised to be affected (faster growth)
The researcher measures the dependent variable for both groups
Everything else is kept the same between the two groups (e.g. they get same amount of watering and at the same times, the same amount of light and heat and everything else that might affect growth)
Statistical tests are used to help decide whether any difference between the two groups is due to the independent variable or just random chance
If all these elements aren’t present then it isn’t
an experiment. If you’re not sure what kind of study something is you can
always just call it “a study” – that’s a catch-all term.
Why your tutor wrote "It's Not An Experiment" on your essay
An experiment is a special type of study. It's the only kind of study that can demonstrate a cause-effect relationship. In an experiment:
- The researcher is trying to test a cause-effect hypothesis,
e.g. does lemonade make plants grow faster?
- There are (at least) two groups (two identical groups of plants)
- One is
a control group (the group
that gets watered with water)
- One (or more) is an experimental group (the group that gets watered with lemonade)
- There is an independent variable, which is the
thing hypothesised to have an effect (the lemonade)
- The researcher controls which group gets the independent variable and which group doesn't
- There is a dependent variable, which is the
thing hypothesised to be affected (faster growth)
- The researcher measures the dependent variable for both groups
- Everything else is kept the same between the two groups (e.g. they get same amount of watering and at the same times, the same amount of light and heat and everything else that might affect growth)
- Statistical tests are used to help decide whether any difference between the two groups is due to the independent variable or just random chance
If all these elements aren’t present then it isn’t an experiment. If you’re not sure what kind of study something is you can always just call it “a study” – that’s a catch-all term.