A researcher for a consumer products company is field testing a new formula for laundry detergent. He has contracted with 60 families, each with two children, who have agreed to test the product. He randomly assigns 30 families to the group that will use the new formula and 30 to the group that will use the company's current detergent formula. The most important reason for this random assignment is that
(a) randomization makes the analysis easier since the data can be collected and entered into the computer in any order
(b) randomization eliminates the impact of any confounding variables
(c) randomization is a good way to create two groups of 30 families that are as similar as possible, so that comparisons can be made between the two groups
(d) randomization ensures that the study is double-blind
(e) randomization reduces the impact of outliers
Answer: C