# Probability and Statistics Terms

## Get down with the lingo

### Bar Graph

A representation of data that uses rectangular bars to show the magnitude of categorical variables. Useful in all sorts of real-life situations.

### Bivariate Data

Data that deals with relationships between two variables. Talk about double trouble.

### Box And Whisker Plot

A representation of data that displays the range and quartiles of the data set. Looks like a kitty cat when you squint and tilt your head to the left.

### Categorical Data

Data that can be organized into mutually exclusive groups or categories.

### Combination

One of all possible ways of choosing objects out of a larger group where order does not matter. Not Judge Judy's favorite math concept, that's for sure. The formula is .

### Continuous Data

A type of data for which there's no separation between the possible values.

### Correlation

The measure of the linear relationship between two variables. Can be positive or negative, depending on which side of the bed it woke up on.

### Discrete Data

A type of data for which there's only a finite number of possible values. For example, the integers are discrete because there's no integer between 1 and 2, or between 2 and 3, etc. Also, they're very good at keeping secrets.

### Event

A set of outcomes of an experiment.

### Factorial

The product of all the integers from n down to 1: n! = n × (n – 1) × (n – 2) . . . × 2 × 1. The most excited of all key terms.

### Graph

A diagram representing data or relationship(s) between variables.

### Histogram

A representation of data that uses rectangular bars to show the magnitude of quantitative variables.

### Independent Event

Events A and B are independent if the outcome of event A has no effect on the outcome of event B. It's grown up! It can do what it wants!

### Interquartile Range

The difference between the third and the first quartile.

### Linear Regression

Fitting a straight line to a set of data points to find the linear relationship between the dependent and independent variables.

### Mean (Average)

The sum of all the data points divided by the number of data points.

### Median

The middle value of a list of data points.

### Mode

The data point with highest frequency.

### Mutually Exclusive Event

Events A and B are mutually exclusive if the occurrence of event A implies event B can't occur. They had a bad breakup last year, and they just refuse to be in the same room.

### Odds

The ratio of the probability that an event will happen to the probability that it will not happen.

### Outliers

Data points that are numerically far away from the rest of the data set. The loners of the group, if you will.

### Permutation

One of all possible rearrangements of a collection of objects where the order of the objects is super important. To arrange n objects in r ways, we use the formula .

### Pie Chart

A circular graph divided into sectors, where the area of each sector is proportional to the relative size of the quantities represented. Also incredibly useful in real life.

### Probability

Likelihood or chance of the occurrence of an event.

### Qualitative Data

Data that can be represented with qualities instead of numbers, like "soft" or "muscular" or "caffeinated."

### Quantitative Data

Data that can be represented with numbers.

### Quartiles

A set of points that divide the data set into three equal parts.

### Scatter Plot

A graph of points showing the relationship between two variables.

### Stem And Leaf Plot

A representation of data where each data point is split into a leaf and a stem. The leaf is usually the last digit, and the stem consists of the other digits.

### Univariate Data

Data with only one variable. Not to be confused with data on a unicycle.