# Errata for Think Stats

The errata list is a list of errors and their corrections that were found after the product was released. If the error was corrected in a later version or reprint the date of the correction will be displayed in the column titled "Date Corrected".

The following errata were submitted by our customers and approved as valid errors by the author or editor.

Color Key: Serious Technical Mistake Minor Technical Mistake Language or formatting error Typo Question Note Update

Version Location Description Submitted By Date Submitted Date Corrected
Printed, PDF, Safari Books Online, Other Digital Version
Page 4
Exercise 1-2, bullet point 3

URL has changed. Was: http://nsfg.icpsr.umich.edu/cocoon/WebDocs/NSFG/public/index.htm Now: http://www.icpsr.umich.edu/nsfg6/ Thanks to Jeff Pickhardt for letting me know.

Allen B. Downey

Feb 14, 2012  May 15, 2012
Other Digital Version
13
1st paragraph

Original sentence: "... a formula for variance with n -1 in the denominator, rather than n. This statistic is called the “sample variance,” and it is used to estimate the variance in a population using a sample. We will come back to this in Chapter 8." "sample variance" should be "unbiased variance"

Note from the Author or Editor:
Change this sentence to "This statistic is used to estimate the variance in a population using a sample."

Hidetosi Sirai  Jan 27, 2014
Other Digital Version
23
Ch2 Sec on 'Variance' last paragraph of Sec.

This is in the ePub, which I'm reading on my iPad: "This statistic is called the “sample variance,” and it is used to estimate the variance in a population using a sample. We will come back to this in Chapter ." That's right. Chapter... what? No number or reference. In the PDF the quote is: "This statistic is called the “sample variance,” and it is used to estimate the variance in a population using a sample. We will come back to this in Chapter 8." Please fix this in the ePub..

Note from the Author or Editor:
I don't have the ePub version, so I can't confirm. Also, these links get auto-generated, so I can't fix it.

Leo Marihart  Sep 09, 2011
Printed
Page 30
last paragraph

From the referred URL (http://coolrunning.com/results/10/ma/Apr25_27thAn_set1.shtml) there is no division "F2029". The correct division would be "F2039".

Note from the Author or Editor:
The submitter is correct. I have made this change and checked in a modified XML file (revision 518192).

Jonathan Palardy  Jun 09, 2012
Printed
Page 35
Figure 4.3

The scale of the figure is incorrect. Should be log y and linear x.

Allen B. Downey

Sep 16, 2011  Sep 21, 2011
PDF
Page 37
Last paragraph

The median of an exponential distribution is given as log(2)/lambda. Shouldn't that be ln(2)/lambda?

Note from the Author or Editor:
Yes, that would be clearer. Thanks!

Anonymous  Jun 28, 2012
PDF, Other Digital Version
Page 44

"What conclusion do you draw about the distribution of sizes for cities and towns? You can download a solution from http://populations_cdf.py." Link should be http://thinkstats.com/populations_cdf.py

Ernie Braganza  Jul 28, 2011  Sep 21, 2011
Printed
Page 53
3nd display equation

The formula for the binomial coefficient is incorrect.

Allen B. Downey

Sep 16, 2011  Sep 21, 2011
Printed, PDF, ePub, Mobi, Safari Books Online, Other Digital Version
Page 63
3rd equation from the bottom

"dx" of the right edge is missing

Note from the Author or Editor:
Looks like this is page 66 of version the paper edition. Third equation from bottom should have dx at the end.

Anonymous  Sep 10, 2012
PDF
Page 68
last equation (last paragraph)

Note from the Author or Editor:
Please add a minus sign (-) before \lambda Should be: $\PDF_Z(z) = \infint \PDF_X(x)~\PDF_Y(z-x) \spa dx = \infint \lambda e^{-\lambda x}~\lambda e^{-\lambda (z-x)} dx$

Christoph Lendenmann  May 27, 2013
Printed, PDF, ePub, Mobi, Safari Books Online, Other Digital Version
Page 83
2nd and 3rd equations

The symbols of normal distribution N is required before the parentheses.

Note from the Author or Editor:

Anonymous  Sep 10, 2012
PDF
Page 95
bottom

Note from the Author or Editor:

Christoph Lendenmann  Jun 01, 2013
Printed, PDF, ePub, Mobi, Safari Books Online, Other Digital Version
Page 99
3rd equation's numerator

\sigma dx_{i}dy_{x} should be \sigma dx_{i}dy_{i}

Note from the Author or Editor: