how readily we spread a little butter over the whole universe.
Some time ago a group of social workers in Sheffield, England, started out to substitute an accurate picture of the mental equipment of the workers of that city for the impressionistic one they had.[1] They wished to say, with some decent grounds for saying it. how the workers of Sheffield were equipped. They found, as we all find the moment we refuse to let our first notion prevail, that they were beset with complications. Of the test they employed nothing need be said here except that it was a large questionnaire. For the sake of the illustration, assume that the questions were a fair test of mental equipment for English city life. Theoretically, then, those questions should have been put to every member of the working class. But it is not so easy to know who are the working class. However, assume again that the census knows how to classify them. Then there were roughly 104,000 men and 107,000 women who ought to have been questioned. They possessed the answers which would justify or refute the casual phrase about the "ignorant workers" or the "intelligent workers." But nobody could think of questioning the whole two hundred thousand.
So the social workers consulted an eminent statistician, Professor Bowley. He advised them that not less than 408 men and 408 women would prove to be a fair sample. According to mathematical calculation this number would not show a greater deviation
