Find the expected value of X?

A fair die is rolled and the number of dots showing is recorded. A random variable X is defined to be 1 if the result is greater than 3, and 4 if the result is less or equal to 3.





a. 1/2


b. 5/2


c. 9/2


d. 11/2


e. none of the others

Find the expected value of X?
x1*p(x1) + x2*p(x2)





x1 = 1 for event dots%26gt; 3,


x2 = 4 for event dots%26lt;=3.


These are equally probable because there are 6 dots on the die.





1*(1/2) + 4*(1/2)
Reply:i dont get it......but still 10x 4 d points
Reply:do your own homework!!





Sheesh





think about it.


how many sides on a fair die (this is not Dungeons and Dragons so we can safely assume 6)





so with a 6-sided die and if the number rolled are one of the numbers 4,5,6 (which co-incidentally is half of 6) it gets a value of 1 and if its numbers 1,2,3 it gets a value of 4.





so its a 50:50 chance that a value of 1 or 4 is produced (kinda like flipping a coin) so what would happen if first a 1was rolled on the die and after that a 6 was rolled - what would x be equal to?