Question

We perform an experiment that consists of independent trials where the probability of success is p = 0.25. (a) Let X be the number of successes in 800 trials. Using the appropriate approximation, calculate P{X > 220}.

Answer 1

0.0482

Explanation:

Given the following :

Probability of success : p(success) = 0.25

Number of trials = 800

X = number of successes

Calculate P(X > 220)

The problem above can be solved using the binomial probability formula:

P(X > 220) = P(X = 221) + P(X =222)... + P(X =800)

To save computation time, we coild use the online binomial probability calculator :

P(X > 220) = 0.0482

The binomcdf function of a graphing calcukatur can also be used :

1 - binomcdf(800, 0.25, 220)

1 - (0.95177363855) = 0.04822