intro to Statistics exam 1

Statistics

The science of learning from data

statistic

A numerical summary of data

data

Systematically recorded information in a context

Why

Determines the purpose of the study

Who

• Corresponds to the rows of a data table

• The people (or items) that we want information about

What

• Characteristics of the who

• Also called variable

Quantitative

measure data in UNITS> interval & ratio

Qualitative

can’t math> nominal & ordinal

nominal

labelled into mutually exclusive categories within a variable. These categories cannot be ordered in a meaningful way.

ordinal

ranked {gold, silver, bronze}

interval

numicial scale BUT no fix 0 {temperature}

Ratio

numicial scale BUT fix 0 {age, km/hr}

Cross-sectional data

• Several variables measured all at the same time

• Like a snapshot of data taken at a single point in time

Longitudinal data

• Same variable(s) measured at different points in time

• Measurements should be at regular intervals to be most helpful