Let X be the number of tails that come up when a coin is tossed three times. Calculate the expected value of the given random variable X.
A) $E ( X ) = 2$
B) $E ( X ) = 3$
C) $E ( X ) = 6$
D) $E ( X ) = 1.5$
E) $E ( X ) = 2.25$

Question

Let X be the number of tails that come up when a coin is tossed three times. Calculate the expected value of the given random variable X.  
A) $E ( X ) = 2$
B) $E ( X ) = 3$
C) $E ( X ) = 6$
D) $E ( X ) = 1.5$
E) $E ( X ) = 2.25$

Quizplus · Accepted Answer

The expected value $E(X)$ of a random variable $X$ representing the number of tails in three coin tosses is calculated by multiplying each outcome by its probability and summing these products. The probability of getting a tail in a single toss is $0.5$. For three tosses, the expected value is $3 \times 0.5 = 1.5$.

Let X Be the Number of Tails That Come Up E(X)=2E ( X ) = 2E(X)=2

Let X Be the Number of Tails That Come Up $E ( X ) = 2$