You roll a standard 6-sided die. Find the expected value for each experiment.
(a) You earn 6 points for each dot on the side that lands up.

points

(b) You earn 6 points if it lands on a composite number and lose 6 points if it does not land on a composite number.

a.) Expected value on earning points= 21

b.) Expected value on earnings for composites = -1

Step-by-step explanation:

Expected value = [(6*1 + 6*2 + 6*3 + 6*4 + 6*5 + 6*6 ) ]* (1/6) = 6*(7)/2 = 21

b.)   how many composite numbers from 1 to 6

4 and 6

so...

Expected Value of earning =  [(-6*1 - 6*2 - 6*3 + 6*4 - 6*5 + 6*6 ) ]* (1/6) =

-1 - 2 - 3 + 4 - 5 + 6 =  -1

207/8 is the right