Stats

Question 1

Sab

Answer 1

Eab - ((Ea)(Eb)/n

Question 2

Y on x regression line

Answer 2

a = y_ - bx_
b = sxy/xx

Question 3

Expectation of combinations of random variables

Answer 3

E(aX + bY + c) = aE(X) + bE(Y) + c

Question 4

Variance of combinations of random variables

Answer 4

Var(aX + bY + c) = a^2 Var(X) + b^2 Var(Y)

Question 5

Sample mean, from a sample of n observations of a random variable.

Answer 5

Random variable with mean E(X) and variance Var(X)/n

Question 6

Poisson distribution conditions

Answer 6

Random events
Events independent of each other
Average rate of events is constant

Question 7

E(X) and Var(X) of poisson

Answer 7

lambda

Question 8

If X ~ Po(a), Y ~ Po(b), and Z = X+Y, Z~

Answer 8

Po(a+b)

Question 9

Spearman’s rank

Answer 9

1-(6sumd^2 / n(n^2 - 1)

Question 10

Spearman’s hypothesis test

Answer 10

H0, association
H1, no association
If rs less than value from tables, do not reject.
If greater, reject.

Question 11

Normal hypothesis test

Answer 11

h0: mean is as given
h1: mean is > < != given, where mu is population mean