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xxviii
Contents.
| §19, 20. | Combination of testimony. | |
| 21, 22. | Scientific meaning of a miracle. | |
| 23, 24. | Two distinct prepossessions in regard to miracles, and the logical consequences of these. | |
| 25. | Difficulty of discussing by our rules cases in which arbitrary interference can be postulated. | |
| 26, 27. | Consequent inappropriateness of many arguments. | |
| CHAPTER XVIII. | ||
| ON THE NATURE AND USE OF AN AVERAGE, AND ON THE DIFFERENT KINDS OF AVERAGE. | ||
| § 1. | Preliminary rude notion of an average, | |
| 2. | More precise quantitative notion, yielding (1) the Arithmetical Average, | |
| 3. | (2) the Geometrical | |
| 4. | In asymmetrical curves of error the arithmetic average must he distinguished from, | |
| 5. | (3) the Maximum Ordinate average, | |
| 6. | (4) and the Median. | |
| 7. | Diagram in illustration. | |
| 8—10. | Average departure from the average, considered under the above heads, and under that of | |
| 11. | (5) The (average of) Mean Square of Error. | |
| 12—14. | The objects of taking averages. | |
| 15. | Mr Galton's practical method of determining the average, | |
| 16, 17. | No distinction between the average and the mean. | |
| 18—20. | Distinction between what is necessary and what is experimental here. | |
| 21, 22. | Theoretical defects in the determination of the 'errors'. | |
| 23. | Practical escape from these. | |
| (Note about the units in the exponential equation and integral.) | ||
