Question

Find the probability of having 2,3 or 4 successes in five trials of a binomial experiment in which the probability of success is 40% Round to the nearest tenth of a percent

Answer 1

65.3%.

Explanation:

The general formula is:

nCr p^r (1 - p)^(n-r) where n = number of trials, p =probability of success on one trial , r = the given number of successes

So for 2, 3 or 4 success ;

probability = 5C2 (0.4)^2 (0.60)^(5-2) + 5C3 (0.4)^3 (0.60)^(5-3)

+ 5C4 (0.4)^4 (0.60)^(5-4)

= 0.3456 + 0.2304 + 0.0768

= 0.6528.