A consumer research organization was interested in the influence of type of water on the effectiveness of a detergent. Test batches of washings were run in four randomly chosen machines having a particular type of water - soft, moderate, and hard. All batches had equal numbers of oil-stained rags and after each washing the number of rags stilled stained 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 level of .01, would you conclude that the type of water influences the effectiveness of the detergent?