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Intro to Statistics with R: Introduction

Types of variables

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Intro to Statistics

! Nominal

! Ordinal

! Interval

! Ratio

Types of variables

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Nominal variables

!

Used to assign individual cases to categories

! DataCamp students come from many diff erent countries

!   Country of origin is a nominal variable

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Intro to Statistics

Ordinal variables

!

Used to rank order cases

! Countries may be ranked according to overallpopulation

!   Ranking is an ordinal variable

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Intro to Statistics

! Used to rank order cases where the distance, orinterval, between each value is equal

! Each country has a longitude and latitude

!   Longitude and latitude are interval variables

Interval variables

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Ratio variables

!

Same as interval variables but have a “true zero”

! Population (Population of 0 = extinct)

! Temperature °K (the Kelvin scale)

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Let’s Practice!

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Intro to Statistics with R: Introduction

On the Theory ofScales of

Measurement

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Types of variables

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Race results

2:34:01

2:34:03

2:34:09

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Types of variables

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Intro to Statistics with R: Introduction

Let’s Practice!

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Intro to Statistics with R: Introduction

Quick summary

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Intro to Statistics

Types of variables

!

Independent vs. dependent variables! Vaccine trial example

! Independent = treatment (nominal)

! Dependent = disease rate (ratio)

i i

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Discrete vs. continuous

Variable Type Discrete or Continuous?

Nominal

Ordinal

Interval

Ratio

Discrete

Discrete

Continuous

Continuous

I S i i

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Summary

!

Know your variable types!! Nominal

! Ordinal

! Interval

! Ratio

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Congratulations!