Chapter 2: Basic Statistics

Question 1

Covariance of independent variables:

Answer 1

ZERO

Question 2

Population Mean:

Answer 2

E(X)=Summation of xi*pi

Question 3

Sample Mean:

Answer 3

xbar=1/n*Summation of xi

Question 4

Population Variance:

Answer 4

Var(X)=E(X-E(X))^2

Question 5

Sample Variance:

Answer 5

Var(x)head=1/(n-1)*Summation of (xi-xbar)^2

Question 6

Population Covariance:

Answer 6

Cov(X,Y)=E((X-E(X))*(Y-E(Y)))

Question 7

Sample Covariance:

Answer 7

Cov(X,Y)head=1/(n-1)*Summation of (xi-xbar)(yi-ybar)

Question 8

Population Correlation Coefficient:

Answer 8

Corr(X,Y)=Cov(X,Y)/Square of (Var(X)*Var(Y))

Question 9

Sample Correlation Coefficient:

Answer 9

Corr(X,Y)head=Cov(X,Y)head/Square of (Var(X)head*Var(X)head)