11.2 Eighteen freshwater clams were randomly assigned to 3 groups of 6 each. One group was placed in the pond water from which the clams were collected, one group was placed in deionized water, and one group was placed in a solution of 0.5 mM sodium sulfate. At the end of a specified time period, blood potas- sium levels were determined. Do the treat- ments affect blood potassium levels (M K+)? Pond Deionized Sodium Water Water Sulfate .518 .318 .393 .523 .342 .415 .495 .301 .351 .502 .390 .390 .525 .327 .385 .490 .320 .397 Data from J. Schiede