If the probability of success is .25, what is the probability of obtaining the first success within the first three trials?
A).4218
B).5781
C).1406
D).2228

Question

Quizplus · Accepted Answer

The probability of obtaining the first success within the first three trials can be calculated using the geometric distribution. The probability of success on the first trial is 0.25. The probability of failing the first trial and succeeding on the second is 0.75 * 0.25. The probability of failing the first two trials and succeeding on the third is 0.75^2 * 0.25. Adding these probabilities gives 0.25 + 0.75*0.25 + 0.75^2*0.25 = 0.5781.

If the Probability of Success Is