Hacker News new | ask | show | jobs
by jstanley 1390 days ago
Good idea (for integer-valued measurements), but you can do it without having to bother calculating all fractions with denominator N.

Let's say the reported mean is called m and the sample size is N. Multiply m and N together. Ideally mN should be almost an exact integer. Find ceil(mN)/N and floor(mN)/N and see if they're the same as the reported m, within precision limits.

Example: m=6.24, N=13

mN = 81.12 (exact)

81/13 = 6.231

82/13 = 6.308

So there is no integer numerator (for denominator 13) that gives 6.24, to 2 decimal places, so 6.24 is a mistake or a lie.