A scientist was asked to test the effect of a new vitamin for rats. His hypothesis was that young rats that had vitamins added to their food would
gain weight faster than young rats fed a normal diet. He predicted that if
young rats were fed vitamins, then they would gain more weight by the end of
the experiment. He tested the effect of adding vitamins to some of the rats'
diet by measuring the amount of weight each rat gained after three months.
He then determined the average weight gained in each group. To analyze his
results, he put the data he collected into the table shown below.
Rats fed normal diet
Rats fed normal diet and vitamins
Rat
Starting
Ending
weight
weight
Difference
in weight
Rat#
Starting Ending
weight weight
Difference
In weight
1
256 g
320 g
649
1
249 g
3429
939
2
2749
3479
730
2
2219
3079
86 9
3
2099
2689
599
3
2789
3819
103 g
Average
weight
gain
659
Average
weight
gain
949
What was the control group for this experiment?