X e - 17 x 576.48/259.85 = 37.71. From the row for 17 df in Table 13.3 we see that a X 2 value of 37.71 lies between 35.72, associated with an area under the curve in the right tail of 0.5%, and 40.78, associated with an area of 0.1%. By interpolation, which is approximate, the area associated with 37.71 will be about 0.4 of the way from 0.5 % to 0.1%, or about 0.3 %.

If we sampled standard deviations repeatedly from a normal patient population, we would find a standard deviation of 24.01 or larger only about 3 times out of 1000.