The third, by Tversky and Kahneman’s account: they reported that a typical English text holds twice as many words with K in third position as words that start with K. In 1973 they asked 152 people to judge, for K and four other letters, whether each appears more often first or third; all five, they reported, are more frequent in third position. A majority judged each letter more frequent in first position, and 105 of the 152 judged the first position more likely for most of the letters (Tversky & Kahneman, 1973). Later work by Sedlmeier, Hertwig and Gigerenzer, in 1998, challenged the finding.
Tversky, A., & Kahneman, D. (1973). Availability: A heuristic for judging frequency and probability. Cognitive Psychology, 5(2), 207-232.