Swineford, F. (1941). Analysis of a personality trait. Journal of Educational Psychology, 32(6), 438-444.
http://dx.doi.org/10.1037/h0059194
344 pupils were given 4 tests in different subject matter fields. A gambling or G score was computed by permitting each pupil to ask for 2, 3, or 4 points for each question answered correctly, with twice the number asked for being deducted if the question was answered incorrectly. Boys were consistently higher in G scores than girls, both sexes tended to gamble more on unfamiliar than on familiar material, and G scores are independent of scores on tests from which they are computed. The distributions of G scores are not normal, but are positively skewed with modes near zero. "Intercorrelations among the G scores calculated from the four tests are sufficiently high to yield a multiple-correlation coefficient of .85 when all four measures are combined in a regression estimate of the G factor." (PsycINFO Database Record (c) 2016 APA, all rights reserved)