Formulas

Question 1

Standard deviation and variance (sample)

Answer 1

Square root of [sum of the (x values take away the mean)^2 divided by the number of samples -1. Variance you don’t square

Question 2

Standard deviation and variance (population)

Answer 2

Do not divide by number of samples minus 1. Just the number of samples.

Question 3

Coefficient of variation

Answer 3

standard deviation divided by mean multiplied by 100

Question 4

Probability of event E

Answer 4

Number of outcomes corresponding to event E divided by total number of outcomes (essentially a fraction)

Question 5

Standardization for normal comparison

Answer 5

z = [X-mean] divided by standard deviation

Question 6

F ratio

Answer 6

explained variance divided by unexplained variance

Question 7

Explained variance

Answer 7

[Sum of (best estimate of y - mean of y)^2] divided by number of predictors

Question 8

Unexplained variance

Answer 8

[Sum of (individual observations of Y - best estimation of Y)^2] divided by (n-number of predictors-1)

Question 9

Variance on regression?

Answer 9

Sum of squares divided by degrees of freedom

Question 10

Regression coefficient

Answer 10

Regression sum of squares of Y divided by total sum of squares

Question 11

Durbin Watson autocorrelation statistic

Answer 11

Sum of successive squared differences divided by sum of squared residuals