A fair coin is tossed 8 times. What is the probability of obtaining exactly 4 heads if it is known that at least 1 head appeared?

Round your answer to 4 decimal places

Question

A fair coin is tossed 8 times. What is the probability of obtaining exactly 4 heads if it is known that at least 1 head appeared?

Round your answer to 4 decimal places

anonymous · Answer

If, in the sequence of 8 tossings, that 1 head already appeared and counted as one of the 4? (Just clarifying.)

anonymous · Answer

This is sort of a trick question. Stating that 1 head appeared just means that in the subsequent 7 tosses, what are the odds that you will get 3 more heads?

anonymous · Answer

If thats the case then i would want 3 successes in a number of 7 trials now with the probability of 1/2

anonymous · Answer

Bayes rulez! (C(7,3)*0.5^7)/(1-0.5^8)...round that urself