The expected length of code for one encoded symbol is

where
is the probability of picking the letter
, and
is the length of code needed to encode
.
is given to us, and we have

so that we expect a contribution of

bits to the code per encoded letter. For a string of length
, we would then expect
.
By definition of variance, we have
![\mathrm{Var}[L]=E\left[(L-E[L])^2\right]=E[L^2]-E[L]^2](https://tex.z-dn.net/?f=%5Cmathrm%7BVar%7D%5BL%5D%3DE%5Cleft%5B%28L-E%5BL%5D%29%5E2%5Cright%5D%3DE%5BL%5E2%5D-E%5BL%5D%5E2)
For a string consisting of one letter, we have

so that the variance for the length such a string is

"squared" bits per encoded letter. For a string of length
, we would get
.
Answer:
He will run 60 kilometers.
Step-by-step explanation:
285 / 95 = 3
20 x 3 = 60
480 is 100%
48 = 10%
480 = 100%
Answer:
125 g
Step-by-step explanation:
500/2=250
250/2=125
Answer:
1, 2, 5 and 6 are the answers.
Step-by-step explanation:
2 is correct because the arrow shows that the number line continues till infinity. 5 is correct because any fraction is possible as no restriction of integer value is placed. Any number less than 7 is not included. There are some confusions with 1 as it's not a solid color, So, I assume -7 is not included.