first part of 4th vis lesson

3-Data-Visualization/13-visualization-relationships/README.md

@@ -10,6 +10,88 @@ It will be interesting to visualize the relationship between a given state's pro
 
 [Pre-lecture quiz]()
 
+In this lesson, you can use Seaborn, which you use before, as a good library to visualize relationships between variables. Particularly interesting is the use of Seaborn's `relplot` function that allows scatter plots and line plots to quickly visualize '[statistical relationships](https://seaborn.pydata.org/tutorial/relational.html?highlight=relationships)', which allow the data scientist to better understand how variables relate to each other.
+## Scatterplots
+
+Use a scatterplot to show how the price of honey has evolved, year over year, per state. Seaborn, using `relplot`, conveniently groups the state data and displays data points for both categorical and numeric data. 
+
+Let's start by importing the data and Seaborn:
+
+```python
+import pandas as pd
+import matplotlib.pyplot as plt
+import seaborn as sns
+honey = pd.read_csv('../../data/honey.csv')
+honey.head()
+```
+You notice that the honey data has several interesting columns, including year and price per pound. Let's explore this data, grouped by U.S. state:
+
+| state | numcol | yieldpercol | totalprod | stocks   | priceperlb | prodvalue | year |
+| ----- | ------ | ----------- | --------- | -------- | ---------- | --------- | ---- |
+| AL    | 16000  | 71          | 1136000   | 159000   | 0.72       | 818000    | 1998 |
+| AZ    | 55000  | 60          | 3300000   | 1485000  | 0.64       | 2112000   | 1998 |
+| AR    | 53000  | 65          | 3445000   | 1688000  | 0.59       | 2033000   | 1998 |
+| CA    | 450000 | 83          | 37350000  | 12326000 | 0.62       | 23157000  | 1998 |
+| CO    | 27000  | 72          | 1944000   | 1594000  | 0.7        | 1361000   | 1998 |
+
+
+Create a basic scatterplot to show the relationship between the price per pound of honey and its U.S. state of origin. Make the `y` axis tall enough to display all the states:
+
+```python
+sns.relplot(x="priceperlb", y="state", data=honey, height=15, aspect=.5);
+```
+![scatterplot 1](images/scatter1.png)
+
+Now, show the same data with a honey color scheme to show how the price evolves over the years. You can do this by adding a 'hue' parameter to show the change, year over year:
+
+> ✅ Learn more about the [color palettes you can use in Seaborn](https://seaborn.pydata.org/tutorial/color_palettes.html) - try a beautiful rainbow color scheme!
+
+```python
+sns.relplot(x="priceperlb", y="state", hue="year", palette="YlOrBr", data=honey, height=15, aspect=.5);
+```
+![scatterplot 2](images/scatter2.png)
+
+With this color scheme change, you can see that there's obviously a strong progression over the years in terms of honey price per pound. Indeed, if you look at a sample set in the data to verify (pick a given state, Arizona for example) you can see a pattern of price increases year over year, with few exceptions:
+
+| state | numcol | yieldpercol | totalprod | stocks  | priceperlb | prodvalue | year |
+| ----- | ------ | ----------- | --------- | ------- | ---------- | --------- | ---- |
+| AZ    | 55000  | 60          | 3300000   | 1485000 | 0.64       | 2112000   | 1998 |
+| AZ    | 52000  | 62          | 3224000   | 1548000 | 0.62       | 1999000   | 1999 |
+| AZ    | 40000  | 59          | 2360000   | 1322000 | 0.73       | 1723000   | 2000 |
+| AZ    | 43000  | 59          | 2537000   | 1142000 | 0.72       | 1827000   | 2001 |
+| AZ    | 38000  | 63          | 2394000   | 1197000 | 1.08       | 2586000   | 2002 |
+| AZ    | 35000  | 72          | 2520000   | 983000  | 1.34       | 3377000   | 2003 |
+| AZ    | 32000  | 55          | 1760000   | 774000  | 1.11       | 1954000   | 2004 |
+| AZ    | 36000  | 50          | 1800000   | 720000  | 1.04       | 1872000   | 2005 |
+| AZ    | 30000  | 65          | 1950000   | 839000  | 0.91       | 1775000   | 2006 |
+| AZ    | 30000  | 64          | 1920000   | 902000  | 1.26       | 2419000   | 2007 |
+| AZ    | 25000  | 64          | 1600000   | 336000  | 1.26       | 2016000   | 2008 |
+| AZ    | 20000  | 52          | 1040000   | 562000  | 1.45       | 1508000   | 2009 |
+| AZ    | 24000  | 77          | 1848000   | 665000  | 1.52       | 2809000   | 2010 |
+| AZ    | 23000  | 53          | 1219000   | 427000  | 1.55       | 1889000   | 2011 |
+| AZ    | 22000  | 46          | 1012000   | 253000  | 1.79       | 1811000   | 2012 |
+
+
+Another way to visualize this progression is to use size, rather than color. For colorblind users, this might be a better option. Edit your visualization to show an increase of price by an increase in dot circumference:
+
+```python
+sns.relplot(x="priceperlb", y="state", size="year", data=honey, height=15, aspect=.5);
+```
+You can see the size of the dots gradually increasing.
+
+![scatterplot 3](images/scatter3.png)
+
+Is this a simple case of supply and demand? Is there less honey available for purchase year over year, and thus the price increases?
+
+To discover a correlation between price, number of colonies, and yield per colony, let's explore some line charts.
+
+
+
+
+## Multi-line Plots
+
+
+
 ## 🚀 Challenge
 
 ## Post-Lecture Quiz