1 The average height of a male soldier is 70 inches with a s

1. The average height of a male soldier is 70 inches with a standard deviation of 4 inches. The average height of female soldier is 66 inches with a standard deviation of 4 inches. If a male soldier and female soldier are paired up what will be the mean and standard deviation for the difference in heights for each possible pair?

Select one:

a. Mean of 4 inches and standard deviation of 4 inches

b. Mean of 68 inches and standard deviation of 4 inches

c. Mean of 4 inches and standard deviation of 5.66 inches

d. Mean of 4 inches and standard deviation of 0 inches

e. Mean of 68 inches and standard deviation of 5.66 inches

2. Suppose X and Y are random variables with means of 720 and 240 respectively and standard deviations of 6 and 8 respectively. What are the mean and standard deviation of the random variable X + Y?

Select one:

a. 960, 7

b. 960, 10

c. 960, 14

d. 480, 14

3. The Millionaire State Lottery decides to triple all prize amounts for a period of 1 month. What effect will this have on the variance?

Select one:

a. Triple it

b. Quadruple it

c. Double it

d. Increase it nine-fold

4. On your visit to a casino you decide to play two of your favorite games. The mean winings for the first game, Lots of Luck, is -$0.20 (each play costs $1.00). The mean or expected value for the second game, Spinaway, is $-0.30 (each play costs $1.00). You are playing the games at the same time and they are independent of each other. What will be your mean winnings?

Select one:

a. $1.50

b. $0.70

c. -$0.25

d. -$0.50

Solution

1.) Mean = 70-66 = 4

SD = (4^2-4^2)

= 5.66

2.) Mean = 720 + 240 = 960

SD = (6^2+8^2)

= 10

c.) Increase it nine fold

d.) Mean = $-0.5