The following data* represent the number of different macroinvertebrate species collected at 6 stations, located in the vicinity of a thermal discharge, from 1970 to 1977.

To test the hypotheses that the data are unchanging

(a) from year to year, and

(b) from station to station, run Program 10.5. Results are shown in Figure 10.2. Thus both the hypothesis that the data distribution does not depend on the year and the hypothesis that it does not depend on the station are rejected at very small significance levels.

Transcribed Image Text:

Station Year 1 2 3 4 5 6 1970 53 35 31 37 37 40 43 1971 36 34 17 21 30 18 1972 47 37 17 31 45 26 1973 55 31 17 23 43 37 1974 40 32 19 26 45 37 1975 52 42 20 27 26 32 1976 39 28 21 21 36 28 1977 40 32 21 21 36 35