10.17 Below are four sets of five measurements, each set an array of data on the smoothness of a certain type of paper, each set obtained from a different laboratory. Find an approximate P value to test whether the median smoothness can be regarded as the same for all laboratories.

Laboratory Data A 38.7 41.5 43.8 44.5 45.5 B 39.2 39.3 39.7 41.4 41.8 C 34.0 35.0 39.0 40.0 43.0 D 34.1 34.8 34.9 35.4 37.2