Answer: 0.013051
Step-by-step explanation
We have 26 letters to pick from in the set A,B,C,...,X,Y,Z
When repeats are allowed, there are roughly 26^14 = 6.4509975 * 10¹⁹ different 14 letter "words" we can form. Scientific notation is needed because the result is a really large number. Most of these words won't be found in the dictionary as they'll be a string of nonsensical letter patterns.
If repeated letters weren't allowed, then we would have 8.4194178 * 10¹⁷ different permutations. Use the nPr formula with n = 26 and r = 14 to get that value mentioned. Or the scratch work calculation would look like this:
26*25*24*23*22*21*20*19*18*17*16*15*14*13 = 8.4194178 * 10¹⁷ approximately.
From here we divide the two values
(8.4194178 * 10¹⁷)/(6.4509975 * 10¹⁹)
= (8.4194178/6.4509975)*(10¹⁷/10¹⁹)
= 1.3051343*10¹⁷⁻¹⁹
= 1.3051343*10⁻²
= 0.013051343
= 0.013051
There's about a 1.305% chance of randomly typing out a 14 letter word that has no repeated letters.