###
If you can do one task n number of ways and a second m number of ways, then both tasks can be done in n*m ways.

Multiplication principle

###
The P(A) of any event is between 0 and 1 (inclusive)

Probability rule 1

###
If S is the sample space in a probability model, then P(S)=1

Probability rule 2

###
Two events A and B are disjoint if they have no outcomes in common. P(A or B)=P(A)+P(B)

Probability rule 3

###
the complement of A is 1-P(A)

Probability rule 4

###
P(A and B) = P(A)*P(B)

Multiplication rule for independent events

###
P(A or B) = P(A)+P(B) - P(A and B)

General addition rule for unions of two events

###
P(B|A) = P(A and B)/P(A)

Conditional probability

###
if P(B|A) = P(B)

Independent events

###
random variable with either a finite (whole) number value or a countable number

Discrete random variable

###
takes all values in an interval of numbers, described by a density curve.

Continuous random variable

###
mean of X = multiply each possible value by its probability and then add it up

Mean of a discrete random variable

###
variance of x = (x1-mean)^2**p1...(xi-mean)^2**pi

Variance of a discrete random variable

###
if X is a random variable and a and b are fixed numbers, mean of a+bX = a+bmeanX

rule 1 for means

###
if X and Y are random variables, meanx+y=meanx + meany

rule 2 for means

###
bcdf(n, p, k)

bcdf on calculator

###
mean = np

mean of binomial

###
Sx=sqrt(npq)

std. dev of binomial

###
gcdf(p,n)

gcdf on calculator

###
mean = 1/p

Mean of geometric random variable

###
q/p^2

std. dev of geometric random variable

###
P(X>n) = q^n

probability of more than n trials before success

### Please allow access to your computer’s microphone to use Voice Recording.

## We can’t access your microphone!

### Click the icon above to update your browser permissions and try again

Example:

### Reload the page to try again!

Reload

## Press Cmd-0 to reset your zoom

## Press Ctrl-0 to reset your zoom

### It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

## Your microphone is muted

### For help fixing this issue, see this FAQ.