Percentage Points ofH-Distribution for Computing Confidence Limits or Performingt-Tests by Way of the Mean Absolute Deviation

A table to three decimal places is provided for the percentage points of the variate , where d is the mean absolute deviation from the mean of a normal sample of size n, and μ is the population mean. The table is analogous to the table of Student's t-distribution. It makes it possible to compute confidence limits for the mean and to perform various tests of significance by way of the mean absolute deviation instead of the standard deviation. This method is almost as accurate as standard procedures. It is very simple to use, particularly for small samples, and has the additional advantage that results are less sensitive to doubtful outlying observations inasmuch as the mean absolute deviation gives less weight to large deviations than does the standard deviation.