A consumer researchorganization was interested in the influence of type of water onthe effectiveness of a detergent. Test batches of washings were runin four randomly chosen machines having a particular type of water- soft, moderate, and hard. All batches had equal numbers ofoil-stained rags and after each washing the number of rags stilledstained was determined. The following results were obtained.
Number of Rags with Stains
Sample
Observations Soft Moderate Hard
1 0 4 10
2 1 8 5
3 2 3 7
4 1 5 10
Using an alpha levelof .01, would you conclude that the type of water influences theeffectiveness of the detergent?
