1. Measurable Discrete Continuous A failure Indeterminate
Let X = the number of dropped calls experienced per day by customers of a particular cell phone provider. This random variable is 10
Measurable
Discrete
Continuous
A failure
Indeterminate

2. Let Y = the number of dropped calls experienced per day by customers of a particular cell phone provider. Y has the following probability distribution: What is the expected number of dropped calls per day? Y 1 2 3
Prob
.55
.30
.10
.05 10
0.5
0.65
2.0
1.5

3. Let Y = the number of dropped calls experienced per day by customers of a particular cell phone provider. Y has the following probability distribution: What is the standard deviation of dropped calls per day? Y 1 2 3
Prob
.55
.30
.10
.05 10
1.15
0.853
0.652
2.0
1.5

4. X and Y are independent random variables with expected values and standard deviations as shown. What is E(X – Y)?
Exp. Value SD X 80 12 Y 3 10 92 68 34 83

5. X and Y are independent random variables with expected values and standard deviations as shown. What is SD(X – Y)?
Exp. Value SD X 80 12 Y 3 10 9 15
11.62
135
12.37

6. In North Carolina, heights of HS boy basketball players have mean 74 inches and standard deviation 4.5 inches, while girl players have a mean height of 70 inches and standard deviation 3 inches. At a mixed 2-on-2 tournament teams are formed by randomly pairing boys with girls as teammates. On average, how much taller do you expect the boy to be? 10 4” 2”
7.5”
1.5” 3”

7. In North Carolina, heights of HS boy basketball players have mean 74 inches and standard deviation 4.5 inches; girl players have a mean height of 70 inches and standard deviation 3 inches. At a mixed 2-on-2 tournament teams are formed by randomly pairing boys with girls as teammates. What is the standard deviation of the difference in the heights of a boy and girl on a 2-person team? 10
1.5“
7.5”
5.4”
2.25” 4”