SH1660
Name: Section:
Date: Score:
Probably the Most Probable
Discrete Probability Distributions
I. FILL IN THE BLANKS: Fill in the blanks with the correct word/s. (5 items x 1 point)
1. is a table, a graph or a formula listing all possible values that a discrete
random variable can take on, along with the associated probabilities.
2. If a real number ๐ฅ is not a possible value for a random variable ๐ฅ, then it has a probability of
.
3. is a graphical way in expressing the probability distribution. Here, the
rectangles are constructed so their bases of equal width are centered at each value of ๐ฅ and
their heights are equal to the corresponding probabilities given by ฦ(๐ฅ).
4. is a formula that gives the probability function.
5. The properties of a discrete probability distribution are and .
II. PROBLEM SOLVING: Perform what is being asked. Write your answers on the back of this
page.
1. A random variable can assume five (5) values: 0, 1, 2, 3, 4. A portion of the probability
distribution is shown here. (3 items x 2 points)
๐ฅ0 1 2 3 4
๐(X = ๐ฅ) .1 .3 .3 ? .1
a. Find ๐(X = 3).
b. What is the probability that ๐ฅ is greater than 2?
c. What is the probability that ๐ฅ is 3 or less?
2. The following table is a partial probability distribution for the MRA Companyโs projected
profits (๐ฅ=profit in โฑ1000๐ ) for the first year of operation ( the negative value denotes a
loss). (2 items x 2 points)
๐ฅ
ฦ(๐ฅ)
-100 .10
0 .20
50 .30
100 .25
150 .10
200
a. What is the proper value for ฦ(200)? What is your interpretation of this value?
b. What is the probability that MRA will be profitable?
01 Worksheet 1
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