input = {0.47, 2.61, 1.63, -0.98, 0.23, 1.12}

output = {0.5, 1.5, 1.5, .......}

All I did there was to look on the graph for the input data (eg, the first in the sequence is 0.47), then go directly up from the input axis at that point to where you meet the line representing the quantizer function, and look across to see that at that input value, you get an output of 0.5. Repeat for the other items in the input sequence.

Now, that output sequence contains the "symbols" that you will encode, and the probabilities of getting each "symbol" is what was given to you, eg.

P(-1.5)=0.2, P(-0.5)=0.3, P(0.5)=0.4, P(1.5)=0.1

Check out this link, http://en.wikipedia.org/wi

If you still have questions about either of these steps, come back and let us know.