According to a recent report 010 is the probability that a r

According to a recent report, 0.10 is the probability that a randomly-selected American citizen knows that Janet Yellen is the Chair of the Federal Reserve Board of the US Government. Nine Americans are randomly selected. Find the probability that exactly 3 of the 9 Americans selected identifies Ms Yellen as the Chair of the Federal Reserve Board. Round answer to the nearest thousandth (three places after decimal)

Solution

using binomial

probablility = ⁿC_r * p^r * q^n-r   n=9 r=3

   = ⁹C₃ * (0.10)³ * (1-0.10)^9-3

= 0.0446