bell-shaped curve

“Since there is an equal chance of a marble bouncing left or right at each peg, the marble stacks in the bins below will, on average, form the classic bell-shaped curve of normal distribution.”

There's a figure in the book: There's a huge distribution of attitudes that looks like a bell-shaped curve, but the set of people who actually vote for populist parties is disproportionately on the right.

Here the cult of the presidency invests absurd glory and expectations in that office’s occupants, who generally are mediocrities because politicians, like lawyers and plumbers and columnists, etc., produce a bell-shaped curve.

The 328 senators of the previous 50 years have illustrated the tyranny of the bell-shaped curve: a few of them dreadful, a few excellent, most mediocre.

The children of tall men and women were certainly taller than the mean height of the population, but they too varied in a bell-shaped curve, with some taller and some shorter than their parents.*