Noun
heads or tails
(idiomatic) The practice of flipping a coin in the air, to choose between two alternatives based on which side lands face up.
Many best books lists are comprised of tomes so dense and impenetrable that it requires a Master's degree in literature to make heads or tails of them. Source: Internet
I am not smart enough to make heads or tails of authors such as David Foster Wallace. Source: Internet
Our observation can be put into a contingency table with rows corresponding to the coin and columns corresponding to heads or tails. Source: Internet
Start of play At the beginning of a match, an official tosses a coin and allows the captain of the visiting team call heads or tails. Source: Internet
The elements of the contingency table will be the number of times the coin for that row came up heads or tails. Source: Internet
The participants also exhibited the gambler's fallacy, with their selection of either heads or tails decreasing after noticing a streak of that outcome. Source: Internet