Intro to Statistics with R: Introduction
Intro to Statistics with R: Introduction
Histograms & distributions
Intro to Statistics with R: Introduction
Histograms ●
Simple, but useful and informative
●
Used to display a distribution
Intro to Statistics with R: Introduction
Body temperature example
Intro to Statistics with R: Introduction
Body temperature example
Intro to Statistics with R: Introduction
Summary
> # The hist() function hist(Temperature, breaks = 6)
Intro to Statistics with R: Introduction
Let’s Practice!
Intro to Statistics with R: Introduction
Looking at distributions by using histograms (1/2)
Intro to Statistics with R: Introduction
Body temperature example ●
A few school children have influenza (flu)
●
High body temperature
●
Distribution positively skewed
Intro to Statistics with R: Introduction
Histogram: Body temperature °F Positive skew
Intro to Statistics with R: Introduction
Histogram: Body temperature °C Positive skew
Intro to Statistics with R: Introduction
Body temperature example ●
All individuals in sample sick with flu
●
Treated with antibiotics
●
Suppressed body temperature
●
Compare to second (untreated) group
Intro to Statistics with R: Introduction
Histogram: Body temperature °F
Intro to Statistics with R: Introduction
Histogram: Body temperature °F
Intro to Statistics with R: Introduction
Histogram: Body temperature °C
Intro to Statistics with R: Introduction
Histogram: Body temperature °C
Intro to Statistics with R: Introduction
Let's Practice!
Intro to Statistics with R: Introduction
Looking at distributions by using histograms (2/2)
Intro to Statistics with R: Introduction
Histograms ●
Not all distributions are normal
●
Histogram reveals normal distribution (or not)
●
Let's look at more histograms!
Intro to Statistics with R: Introduction
Wine ratings example ●
100 wine experts
●
Rate quality (1-100) of 8 different wines
●
4 red wines and 4 white wines
●
Higher scores = higher quality
Intro to Statistics with R: Introduction
Wine ratings example ●
4 countries, 2 wines each (one red, one white) ●
Argentina
●
Australia
●
France
●
USA
Malbec & Chardonnay Shiraz & Pinot Grigio
Bordeaux & Sauvignon Blanc Cabernet & Riesling
Intro to Statistics with R: Introduction
Wine ratings example ●
Red wines ratings normal
●
White wines ratings not normal
Intro to Statistics with R: Introduction
Let's Practice!
Intro to Statistics with R: Introduction
Quick summary
Intro to Statistics with R: Introduction
Summary ●
Histograms used to display distributions
●
Many distributions are normal
●
But…
Intro to Statistics with R: Introduction
Summary ●
Some distributions not normal, for example: ●
Bimodal
●
Positively skewed
●
Negatively skewed
●
Uniform (platykurtic)
●
High peak (leptokurtic)
Intro to Statistics with R: Introduction
Congratulations!
Histograms & distributions
Intro to Statistics with R: Introduction
Histograms ●
Simple, but useful and informative
●
Used to display a distribution
Intro to Statistics with R: Introduction
Body temperature example
Intro to Statistics with R: Introduction
Body temperature example
Intro to Statistics with R: Introduction
Summary
> # The hist() function hist(Temperature, breaks = 6)
Intro to Statistics with R: Introduction
Let’s Practice!
Intro to Statistics with R: Introduction
Looking at distributions by using histograms (1/2)
Intro to Statistics with R: Introduction
Body temperature example ●
A few school children have influenza (flu)
●
High body temperature
●
Distribution positively skewed
Intro to Statistics with R: Introduction
Histogram: Body temperature °F Positive skew
Intro to Statistics with R: Introduction
Histogram: Body temperature °C Positive skew
Intro to Statistics with R: Introduction
Body temperature example ●
All individuals in sample sick with flu
●
Treated with antibiotics
●
Suppressed body temperature
●
Compare to second (untreated) group
Intro to Statistics with R: Introduction
Histogram: Body temperature °F
Intro to Statistics with R: Introduction
Histogram: Body temperature °F
Intro to Statistics with R: Introduction
Histogram: Body temperature °C
Intro to Statistics with R: Introduction
Histogram: Body temperature °C
Intro to Statistics with R: Introduction
Let's Practice!
Intro to Statistics with R: Introduction
Looking at distributions by using histograms (2/2)
Intro to Statistics with R: Introduction
Histograms ●
Not all distributions are normal
●
Histogram reveals normal distribution (or not)
●
Let's look at more histograms!
Intro to Statistics with R: Introduction
Wine ratings example ●
100 wine experts
●
Rate quality (1-100) of 8 different wines
●
4 red wines and 4 white wines
●
Higher scores = higher quality
Intro to Statistics with R: Introduction
Wine ratings example ●
4 countries, 2 wines each (one red, one white) ●
Argentina
●
Australia
●
France
●
USA
Malbec & Chardonnay Shiraz & Pinot Grigio
Bordeaux & Sauvignon Blanc Cabernet & Riesling
Intro to Statistics with R: Introduction
Wine ratings example ●
Red wines ratings normal
●
White wines ratings not normal
Intro to Statistics with R: Introduction
Let's Practice!
Intro to Statistics with R: Introduction
Quick summary
Intro to Statistics with R: Introduction
Summary ●
Histograms used to display distributions
●
Many distributions are normal
●
But…
Intro to Statistics with R: Introduction
Summary ●
Some distributions not normal, for example: ●
Bimodal
●
Positively skewed
●
Negatively skewed
●
Uniform (platykurtic)
●
High peak (leptokurtic)
Intro to Statistics with R: Introduction
Congratulations!
