1.   It had been a lucky guess, that was all.

2.   It is a very addictive game of logic, deduction, and lots of lucky guesses when you first play.

3.   Maybe they made a lucky guess.

4.   The reporters could not tell whether this was because Kalmbach was a lucky guess or a ridiculous one.

5.   That had just been a lucky guess.

6.   It might have been just a lucky guess.

7.   Lucky guess.

8.   That view has proved correct in the last several months, but it was largely a lucky guess.

9.   With some lucky guesses, sophisticated statistical analysis and a lot of trial and error, meaning could be squeezed from the noise.