So it becomes a fair test and you can make sure you didn't make any mistakes :)
With controlled experiments it is taken into consideration what possible variables there could be and it is taken into account when conducting the experiment. This would mean that controlled experiments would produce more valid data.
Quantitative experiments should be repeated to make sure they are accurate. This also helps to get rid of outliers in the experiment.
It's important to repeat experiments so then you know that you did the experiment right.
Many different experiments are performed and repeated.
When it proves the tests of repeated experiments
To improve their reliability.
Bugs can effect science experiments. If the experiment does not involve bugs yet they end up near or contained within a science experiment then the experiment is no longer valid and has to be repeated.
With controlled experiments it is taken into consideration what possible variables there could be and it is taken into account when conducting the experiment. This would mean that controlled experiments would produce more valid data.
Quantitative experiments should be repeated to make sure they are accurate. This also helps to get rid of outliers in the experiment.
data
help you detect mistakes or measurement errors OR eliminate the need for data analysis