Random variables

What is a random variable?

a variable that assumes numerical values associated with the random outcomes of an experiment, where one (and only one) numerical value is assigned to each sample point. (x)

What are the two types of random variables?

Discrete and Continuous

What is a discrete random variable?

A random variable that assumes a countable number of values

What is a continuous random variable?

A random variable that assumes values corresponding to any of the points contained in an interval.

What is the probability distribution of a discrete random variable?

either a graph, table, or formula that specifies the probability associated with each possible value.

What are the two requirements for the distribution of discrete random variables?

1) P(x) ≥ 0, for all values of x

2) Σp(x) = 1

What is the mean in probability?

A central tendency for the whole data set.

What is the formula for the mean?

μ = E(x) = Σxp(x)

What is variance in probability?

The variance measures how spread out all the sets of data are from the mean.

What is the formula for the variance?

σ² = 𝛴(xi - μ)² / N

What is the standard deviation?

a measure f how much the data is varying from the mean

What is the standard deviation formula?

μ = √μ²