Third batch of notebooks for Think Stats

BlogResearchStatisticsposted by Allen Downey June 4, 2017

As I mentioned in the previous post and the one before that, I am getting ready to teach Data Science in the spring, so...

If you are reading the book, you can get the notebooks by cloning this repository on GitHub and running the notebooks on your computer.  Or you can read (but not run) the notebooks on GitHub:

I’ll post the next batch soon; in the meantime, here are some of the examples from Chapter 7, demonstrating the surprising difficulty of making an effective scatter plot, especially with large datasets (in this example, I use data from the Behavioral Risk Factor Surveillance System, which includes data from more than 300,000 respondents).

Scatter plots

In [2]:
```df = brfss.ReadBrfss(nrows=None)
```
The following function selects a random subset of a `DataFrame`.
In [3]:
```def SampleRows(df, nrows, replace=False):
indices = np.random.choice(df.index, nrows, replace=replace)
sample = df.loc[indices]
return sample
```
I’ll extract the height in cm and the weight in kg of the respondents in the sample.
In [4]:
```sample = SampleRows(df, 5000)
heights, weights = sample.htm3, sample.wtkg2
```
Here’s a simple scatter plot with `alpha=1`, so each data point is fully saturated.
In [5]:
```thinkplot.Scatter(heights, weights, alpha=1)
thinkplot.Config(xlabel='Height (cm)',
ylabel='Weight (kg)',
axis=[140, 210, 20, 200],
legend=False)
```

Allen Downey

I am a Professor of Computer Science at Olin College in Needham MA, and the author of Think Python, Think Bayes, Think Stats and several other books related to computer science and data science. Previously I taught at Wellesley College and Colby College, and in 2009 I was a Visiting Scientist at Google, Inc. I have a Ph.D. from U.C. Berkeley and B.S. and M.S. degrees from MIT. Here is my CV. I write a blog about Bayesian statistics and related topics called Probably Overthinking It. Several of my books are published by O’Reilly Media and all are available under free licenses from Green Tea Press.

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