Stats chapter 4

what is a discrete probability distribution?

a discrete probability distribution lists each possible value a random variable can assume, together with it's probability

a discrete probability distribution must satisfy what conditions

1. the probability of each value of the discrete random variable is between 0 and 1, inclusive.
2. the sum of all the probabilities is 1 .

the mean of a random variable represents

what you would expect to happen for thousands of trials. it is also called the expected value.

discrete random variables represnet

counted data

continuous random variables represent

measured data

volume, age, height and weight are usually

measured data, so they are continuous random variables

in a binomial experiment, what does it mean to say that each trial is independent of the other trials?

if the outcome of one trial does not affect the outcome of the other trials

what happens as the value of n increases and the probability of success remains the same on a histagram

as n increases, the distribution becomes more symmetric

frinding the mean of a binomial distribution

mean = n x p

the variance of the binomial distribution

variation = n x p x q

standard deviatgion of a binomial distribution

standard deviation = square root of npq

q

the probability of failure in a single trial q = 1-p