(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

In a binary communication system all bit bytes are possible, and equally likely. Any bit is equallly likely to be a 1 or 0.

1- what is the probability of oberving a byte with exactly three 1's?

2-if a byte is observed with exactly three i's, what is the probability the first bit is a 1?

2. Relevant equations

combination formulanCp

3. The attempt at a solution

1- I did:

P(exactly three 1's)= C(3,8)/ 2^8

2-

Here I am confused:

I didP( three 1's and 1 is first)=C(2,7)/(2^8)

OR

P(three 1's and 1 is first)=C(3,7)/(2^8)

I cannot see which one is right.

Can someone tell me what I did right and wrong?

Thank you

B

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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# Probability and byte

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