We have a dictionary consisting of 106 words. If we use a binary tree as a spell checker, estimate how many checks might be required to test whether "name" is a valid word.
It takes at most n checks to find an item in a field of 2n - 1 items.
When n = 6, 26 - 1 = 63
When n = 7, 27 - 1 = 127
So, if you have 106 words, it will take a binary search at most 7 checks.