Question

6. A bag contains 8 white marbles and 2 black

marbles. You pick out a marble, record its
color, and put the marble back in the bag. If
you repeat this process 45 times, how many
times would you expect to remove a white
marble from the bag?
1
·T.P. =
X =

Answer 1

36 times

Explanation:

There are 8 white (W) marbles and 2 black(B) marbles

Total number of marbles = 8 + 2 = 10

Since you are replacing whatever marble you pick on each draw, this is a sampling experiment with replacement

Probability of drawing a white marble is the same on each draw
P(W) = 8/10 = 0.8

Since this process is repeated 45 times, the expected number of times you will draw a white marble
E(W) = P(W) x 45

= 0.8 x 45

= 36 times