Smithers believes that a special juice will increase worker productivity. Create two groups of 50 workers each and assign each group the same task (in this case, they are supposed to staple a set of papers). Group A is given the special juice to drink while they work. Group B does not receive the special juice. After an hour, Smithers counts how many stacks of papers each group has made. Group A made 1,587 piles, Group B made 2,113 piles. identify
1. control group
2. independent variable
3. dependent variable
4. what are some of the mentioned control variables?