Another difficulty about statistics is the technical difficulty
of calculation. Before you can even make a mistake in drawing your
conclusion from the correlations established by your statistics you must
ascertain the correlations. When I turn over the pages of Biometrika,
a quarterly journal in which is recorded the work done in the field of
biological statistics by Professor Karl Pearson and his colleagues, I am
out of my depth at the first line, because mathematics are to me only a
concept: I never used a logarithm in my life, and could not undertake to
extract the square root of four without misgiving. I am therefore unable
to deny that the statistical ascertainment of the correlations between
one thing and another must be a very complicated and difficult technical
business, not to be tackled successfully except by high mathematicians;
and I cannot resist Professor Karl Pearson's immense contempt for, and
indignant sense of grave social danger in, the unskilled guesses of the
ordinary sociologist.
Now the man in the street knows nothing of Biometrika: all he knows is
that "you can prove anything by figures," though he forgets this the
moment figures are used to prove anything he wants to believe. If he did
take in Biometrika he would probably become abjectly credulous as to all
the conclusions drawn in it from the correlations so learnedly worked
out; though the mathematician whose correlations would fill a Newton
with admiration may, in collecting and accepting data and drawing
conclusions from them, fall into quite crude errors by just such popular
oversights as I have been describing.