Problem 3. In this exercise, we study the probability of use of English letters. We take an article written by Feynman as our data. The article is entitled There's Plenty of Room at the Bottom". The article is downloadable at the class webpage, in the Homework section. There is also a MATLAB function readtxt.m that is useful. (a) Use the function provided to read the article into MATLAB, keeping only the letters. (b) Estimate the probabilities (frequencies) that the 26 letters are used. (c) Estimate the probabilities of the 26 letters after a letter B. (d) Estimate the probabilities of the 26 letters after letters Q (e) Based on the estimates, decide whether two consecutive letters are independent Note: The MATLAB function find will find indices that satisfy a certain criterion. For exarnple, find (A 'B') will find the indices of elements in matrix A that are equal to the character B