1. Errors of Observation. - 1 Accidental and systematic errors. - 2 Errors and fractional errors. - 3 Estimate of error. - 4 Estimate of the error in compound quantities. - 5 Error in a product. - 6 Error in a quotient. - 7 Use of the calculus. - 8 Error in a sum or difference. - 2. Some Statistical Ideas. - 9 Frequency distributions. - 10 The mean. - 11 Relative frequency. - 12 The median. - 13 Frequency curves. - 14 Measures of dispersion. - 15 The range. - 16 The mean deviation. - 17 The standard deviation. - 18 Evaluation of standard deviation ?. - 19 Sheppard's correction. - 20 Charlier's checks. - 21 The mean and standard deviation of a sum. - 22 Certain special frequency distributions. - 23 The binomial distribution. - 24 The Poisson distribution. - 25 The normal distribution. - 26 Relation between a normal and a binomial distribution. - 27 The mean deviation of a normal distribution. - 28 Area under the normal error curve. - 29 Sampling standard error of the mean. - 30 Bessel's formulae. - 31 Peters' formulae. - 32 Fitting of a normal curve. - 33 Other frequency distributions. - 3. Theory of Errors. - 34 The normal or Gaussian law of error. - 35 Applicability of the normal law of error. - 36 Normal error distributions. - 37 Standard error of a sum or difference. - 38 Standard error of a product. - 39 Standard error of a compound quantity. - 40 Method of least squares. - 41 Weighted mean. - 42 Standard error of weighted mean. - 43 Internal and external consistency. - 44 Other applications of the method of least squares solution of linear equations. - 45 Solution of linear equations involving observed quantities. - 46 Curve fitting. - 47 Line of regression. - 48 Accuracy of coefficients. - 49 Other curves. - References. Language: English