Probability

Question

You are going to draw two candy bars from a large bag containing 22 Snickers bars and 7 Twix bars. (Assume you are going to keep the candy bars.) Tell whether the two draws are independent or dependent.
__________
What is the probability that both candy bars you draw from the bag are Snickers?
__________
(Round to three decimal places.)


You want to find the probability of rolling a sum of 4 on two dice and then rolling a sum of 5 on the next roll. Tell whether these events are independent or dependent.
__________
Calculate the probability
__________
(Round to three decimal places.)

Answer 1

Dependent because drawing the first candy bar alters the 'sample space' of the second draw.

 

P(2 snickers) = 22/29(21/28)

 

In your second problem (about dice), successive rolls are independent, as each roll is the same set of possibilities; the dice ha sno memory!  So just multiply P(sum 4) times P(sum 5).