# cumulative probability

If the total no of trials is 4 and success ratio is 3:1 distributed in two classes.find the binomial probability obtained is 0.125. similarly if total no. of trials is 33 and success ratio is 14:19 distributed in two classes.find the binomial probability obtained is 0.189.

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What is asked for is not clear from the wording. –  André Nicolas Oct 11 '12 at 4:23
The binomial probability mass function is given by $$P(k\mid N, p) = \binom{N}{k} p^k (1-p)^{N-k}$$ You are given $N$, $P$, and $k$, so you should be able to do this easily.