Question

what is the probability when flipping a coin 20 times and use tallly marks to record your and find p(h)​

Answer 1

What is the probability that you'll get folling sequence ?

HHHHHHHHHHHHHHTTTTTT

If you are tossing a coin then this is given by

(1/2)14.(1/2)6=(1/2)20

So the no. of ways in which 14 heads may occer is not 20P14 but 20C14

so the probability of getting 14 heads in any tail of the experiment is given by

20C14 (1/2)14.(1/2)6=20C14(1/2)20

Say 3/4 for heads and 1/4 for tails thenthe probability of getting 14 heads would be

20C14 (3/4)14.(1/4)6

Takking n tails and k as heads

nCk.Pk (1-P)n-k

There is the probability of getting more than 14, you would have to caluculate the cumulative probabilites of getting 15,16,17,19,and20head

could calculate these probailites in the ways explained above and then sum them up