Lecture 13- Binary

Question 1

What is a binary distribution?

Answer 1

Use it to talk about events where there are two outcomes (yes/ no)
Often use 1 and 0 to represent these outcomes

Question 2

What is a binary distribution also known as?

Answer 2

Bernoulli distribution

Question 3

How do you find the mean of a binary distribution?

Do example on slide 274…

Answer 3

Use formula (under discrete distributions)

Times each value by the probability of getting that value and sum

Question 4

How do you find the variance of a binary distribution?

Do example on slide 275…

Answer 4

Use formula under discrete distributions

(x- mean)^2 x probability of getting that value
Do for all values and sum

Question 5

What is a binomial distribution?

Answer 5

A collection of independent binary distributions

Question 6

How do you find the mean and variance of a binomial distribution?

Answer 6

• Sum the values found for the mean/ variance of each binary distribution
• These will all be the same (as condition of binominal is to have n independent trials where probability of each trial is the same= pi) therefore can just times by n
• This results in the formulas under binomial distribution in the sheet

Question 7

What are the three conditions for a binomial distribution?

Answer 7

• Outcome is binary (if more than two can combine/ simplify into two subsets/ categories)
• We have n independent trails (outcome of one doesn’t change as result of the other)
• Probability of success (pi) must stay constant