Variance and Standard Deviation

Question 1

Variance and Standard Deviation

Answer 1

a. Describe the amount of spread, dispersion, or variability of the items in a distribution.
b. Two values that describe how scattered or spread out the scores are from the mean value of the random variable.

Question 2

Variance Formula

Answer 2

σ² = ∑(X − µ) • P(X)

Question 3

Standard Deviation Formula

Answer 3

σ = √ ∑(X − µ) • P(X)

Question 4

Steps to Get the Variance and Standard Deviation

Answer 4

a. Subtract the mean from each value of the random variable X.
b. Square the results obtained.
c. Multiply the results obtained by the corresponding probability.
d. Get the sum of the results obtained to get the variance.
e. Get the square root of the variance to get the standard deviation.