If you look at LAMB, there is an L, A, M, and B
If we were to select a random letter from the word lamb, there would be a 25 percent chance to choose any of the letter, and 25 percent is 25/100 which equals 1/4
To make this easier, I will solve this in a fraction answer
Now, the are 7 letters in ALABAMA. The letter A shows up 4 times out of the seven letters, L shows up 1 time out of seven letters, B shows up 1 time out of the seven letters, and M shows up 1 time out of the 7 given letter.
Therefore, in LAMB, the 4 letters all have an equal chance at getting randomly picked, but in ALABAMA, A's chances of getting picked are more likely while everything else is less likely to be chosen, since it is now out of 7 and a seventh is less than a fourth.
Therefore, A has a higher chance of getting picked in ALABAMA than in LAMB, and L, M, and B have a smaller chance of getting picked in ALABAMA than in LAMB.
I apologize that I couldn't have answered sooner, but I was not given the chance to last night. Hopefully this still helps you