Linear Combination of Random Variables Mean Standard Deviation

Given a variance of 64, what is the standard deviation?

• 8

• 4096

• 0

• 6.8

Which of the following is a measure of variability?

• mean

• median

• mode

• standard deviation

What is the standard deviation for the data given:

• 6.89

• 10.1

• 7.26

• 9

What is the standard deviation for the data given:
{12, 13, 29, 18, 61, 35, 21}

• 293.67

• 15.87

• 17.14

• 41.98

What is the mean of Z if Z = .5Y + 1

• 11.5

• 10.5

• 21

• 9.5

What is the standard deviation of Z if Z = X + 3Y

• 7.87

• 13.45

• 5.62

• 10.23

X: mean = 48, standard d. = 5

Y: mean = 21, standard d. = 2

What is the standard deviation of Z if Z = 4X + 100

• 5

• 20

• 105

• 120

The random variable X has mean 12 and standard deviation 3. The random variable W is defined as W=7+2X. What are the mean and standard deviation of W?

• Mean = 31, Standard Deviation = 6

• Mean = 40, Standard Deviation = 2

• Mean = 25, Standard Deviation = 5

• Mean = 12, Standard Deviation = 3

The distribution of random variable R has mean 10 and standard deviation 4. The distribution of random variable S has mean 7 and standard deviation 3. If R and S are independent, what are the mean and standard deviation of the distribution of R − S?

• Mean = 10 + 7 = 17, Standard deviation = 4 - 3 = 1

• Mean = 10 - 7 = 3, Standard deviation = 4 + 3 = 7

• Mean = 10 / 7 = 1.43, Standard deviation = 4 / 3 = 1.33

• Mean = 10 - 7 = 3, Standard deviation = sqrt(4^2 + 3^2) = 5

The table above shows a television station's advertisement sales. The distribution of sales for one 24-hour day is given. Solve for the standard deviation. Round to the nearest hundredth.

• 35.76

• 268.1

• 16.3

• 1279.35