Suppose someone were to examine the source text of problem 1 and to discover the single-letter source frequencies, 1, 2, 3, and 4, but to remain ignorant of the digram frequencies ij . Suppose this person applies Huffman's algorithm to S2, assuming the relative frequency of sisj among all two-letter source words to be fi f j .
(a) What compression ratio would this person believe they have achieved, given their assumption about the digram frequencies?
(b) What compression ratio would they actually have achieved?