standard_description: Calculate the expected value of a random variable; interpret it as the mean of the probability distribution.
problem_activity: Problem 1
There are four red envelopes, four blue envelopes, and four $1 bills, which will be placed in four of the eight envelopes.
Below is a tree diagram we can use to answer the questions that follow. Write in the probabilities described.
Suppose one $1 bill is placed in a blue envelope, and the three remaining $1 bills are placed in three red envelopes.
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If you choose a blue envelope, what is the probability that you will get the $1?
If you choose a red envelope, what is the probability that you will get the $1?
Problem 2
Suppose the $1 bills are redistributed among the envelopes. Two $1 bills are placed in two blue envelopes, and two $1 bills are placed in two red envelops. Record the probabilities on the tree diagram.
[IMG]
If you choose a blue envelope, what is the probability that you will get the $1?
If you choose a red envelope, what is the probability that you will get the $1?


aligns: no