Entire group of people, animals, or objects that you want information about


A representative smaller part of the population


A particular tendency towards an opinion, usually preconceived or unreasoned


Objective and impartial, gives "balanced information


Descriptive and cannot be numerically measured


Numerical and can be measured


The number of times an event occurs

Relative frequency

The percentage of times an event occurs


A graph to compare a numerical event and its frequencies

Interquartile range

An interval for the middle 50% of the data

Cumulative relative frequency

The accumulation of the percentage of an event occurring


Value such that p percent of the numbers are less than or equal to that value

Standard deviation

Measure of how much the data differs from the mean


A measure of spread, the standard deviation squared

Sample space

The set of all possible outcomes


The likelihood of an event

Mutually exclusive

Two events that cannot happen at the same time

Independent events

Two events in which the occurrence of one does not affect the probability of the other


Arrangement of r objects from a set of n objects where order matters

Lurking variable

An unsuspected event that could be altering the comparison of two variables

Conditional probability

Likelihood of an event to occur given that an events already happened


A model to imitate and event and it's probability

Expected count

Theoretical number of times an event is going on

P value

A number describing the probability of an event


A selection of r objects taken from a set of n objects where order does not matter

Probability distribution

A function that maps each outcome or event onto its probability

Binomial probability

The likelihood of an event with only two possible outcomes

Standard normal distribution

Shows data in the patter of a "bell-shaped" curve with z-scores along the x-axis

Z score

A standardized value giving the standard deviation away from the mean

Simple random sample

A representation of the data in which each piece of data has and equal chance of being selected

Margin of error

A measurement of the accuracy from survey results

Confidence interval

A range of values estimating the mean from a set of data