# Errata ## Errata for Head First Statistics

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
Page xxxvi
Final sentence left column

Should be "her" instead of "my" Dawn Griffiths

Feb 09, 2009  May 11, 2011
Printed
Page p112
The last term on the third line should be mu squared rather than

x squared

Anonymous    Sep 01, 2008
Printed
Page p177
Major change to the page as follows

1st para: Change the formula to
P(Game2|Satisfied) = P(Game2) P(Satisfied|Game2)

------------------------------------------------------------------------------
P(Game2) P(Satisfied|Game2) + P(Game1
P(Satisfied|Game1)

2nd para starting "We've been told..." leave as it is.

3rd para redo: The next thing we need to find is P(Game1)
P(Satisfied|Game1). We've been told that P(Satisfied |Game1) = 0.6, and
also that P(Game1) = 0.8. This means that
P(Game1) P(Satisfied|Game1) = 0.8 x 0.6
= 0.48

4th para redo the calculations:
P(Game2|Satisfied) = P(Game2) P(Satisfied|Game2)

------------------------------------------------------------------------------
P(Game2) P(Satisfied|Game2) + P(Game1)
P(Satisfied|Game1)
= 0.14
-------
0.14 + 0.48
= 0.14
-------
0.62
= 0.226

Anonymous    Sep 01, 2008
Printed
Page p112
The last term on the third line should be mu squared rather than

x squared

Anonymous    Sep 01, 2008
Printed
Page p177
Major change to the page as follows

1st para: Change the formula to
P(Game2|Satisfied) = P(Game2) P(Satisfied|Game2)

------------------------------------------------------------------------------
P(Game2) P(Satisfied|Game2) + P(Game1
P(Satisfied|Game1)

2nd para starting "We've been told..." leave as it is.

3rd para redo: The next thing we need to find is P(Game1)
P(Satisfied|Game1). We've been told that P(Satisfied |Game1) = 0.6, and
also that P(Game1) = 0.8. This means that
P(Game1) P(Satisfied|Game1) = 0.8 x 0.6
= 0.48

4th para redo the calculations:
P(Game2|Satisfied) = P(Game2) P(Satisfied|Game2)

------------------------------------------------------------------------------
P(Game2) P(Satisfied|Game2) + P(Game1)
P(Satisfied|Game1)
= 0.14
-------
0.14 + 0.48
= 0.14
-------
0.62
= 0.226

Anonymous    Sep 01, 2008
Printed
Page 8
4th paragraph

Typo error - should be "showing" and NOT "showingg".

Anonymous  Apr 15, 2009
Printed
Page 37,38
bottom (graph)

The x axis for the graphs are shown as 'Hours', shouldn't it be 'Age Group'?

Anonymous  Oct 23, 2008  May 11, 2011
Printed
Page 61
Table

data set on p61 is mis-copied from p55

Note from the Author or Editor:
First set of numbers should reflect data for the Kung Fu class on page 55 i.e.

19 19 19 20 20 20 20 20 20 21 21 21 145 147

For the second set of numbers, replace 100 with 145 and 102 with 147.

Anonymous  Oct 08, 2008
Safari Books Online
80

\$10000 x 1.1 = \$11000 not \$12000 as the book states

Anonymous  Oct 22, 2008  May 11, 2011
Printed
Page 112
Third line of puzzle solution

I think the last term of the expression on the third line of the puzzle solution should have "mu" squared instead of "x" squared.

Anonymous  Sep 04, 2008  Sep 01, 2008
Printed
Page 177
everywhere

Wrong use of Baye's theorem.
in the denominator P(Game2)P(Dissatisfied|Game2) should be replaced with P(Game1)P(Satisfied|Game1) and all the calculations should be corrected accordingly.

Note from the Author or Editor:
Major change to the page as follows:

1st para: Change the formula to

P(Game2|Satisfied) = P(Game2) P(Satisfied|Game2)
------------------------------------------------------------------------------
P(Game2) P(Satisfied|Game2) + P(Game1
P(Satisfied|Game1)

2nd para starting "We've been told..." leave as it is.

3rd para redo: The next thing we need to find is P(Game1)
P(Satisfied|Game1). We've been told that P(Satisfied |Game1) = 0.6, and
also that P(Game1) = 0.8. This means that
P(Game1) P(Satisfied|Game1) = 0.8 x 0.6
= 0.48

4th para redo the calculations:

P(Game2|Satisfied) = P(Game2) P(Satisfied|Game2)
------------------------------------------------------------------------------
P(Game2) P(Satisfied|Game2) + P(Game1)
P(Satisfied|Game1)

= 0.14
-------
0.14 + 0.48
= 0.14
-------
0.62
= 0.226

Anonymous  Sep 30, 2008  Sep 01, 2008
Printed
Page 179
Last question: "How useful is Bayes Theorem in real life

The question is not written in bold.

Note from the Author or Editor:
The last question of the NDQs should have a paragraph style of Element_NDQ_Question.

Benjamin Poulain  Apr 04, 2009
Printed
Page 202
1st paragraph second sentence.

The middle of the sentence should read ", which is a variable that can take on a set of values," instead of ", which is a variable that can takes on a set of values,".

Anonymous  Dec 25, 2010
Printed
Page 206
6th paragraph (about in the middle of the page)

replace:
"...variance of X, we calculating..."
with:
"...variance of X, we are calculating..."

Anonymous  Sep 24, 2008  May 11, 2011
Printed
Page 233
bullket points, the point on the lower right of the page

the exponents of 'a' and 'b' in the expressions of the Variance are printed in normal size text

Note from the Author or Editor:
In the last line of the final bullet point, the 2's should be exponents. The formatting should be the same as on page 232.

Anonymous  Sep 24, 2008  May 11, 2011
Printed
Page 244

instead of 3500 (prize) you should use 3500 - 500 = 3000 (expected gain)

Note from the Author or Editor:
Add text "Assume you get your \$500 wager back if you win" to the Sharpen Your Pencil exercise and solution on pages 243/244.

Anonymous  Sep 30, 2008  May 11, 2011
Printed
Page 244

The only error I think I've found so far (only on page 244), is in
your "Sharpen Your Pencil". At the bottom it says "We can expect
to win \$168 each time this race is won.". I think you mean to
say that \$168 is expected ever time it is RUN. So, semantics if
you will. It is probably okay as WON, but I think it is better
as RUN.

Anonymous  Nov 10, 2008  May 11, 2011
Printed
Page 256
excercise solution, solution number 2

the final result is not 252 but 2520

Note from the Author or Editor:
The final result for question 2 should be 2520 not 252.

Anonymous  Sep 24, 2008  May 11, 2011
Printed
Page 256
bottom

The last part is wrong too as a result of the previous error.

So it's not 60/252 = 5/21.

It should be 60/2520 = 1/42.

Ho hum.

Note from the Author or Editor:
The final sentence should read "The probability of all 5 camels finishing together is therefore 60/2520 = 1/42."

Anonymous  Oct 29, 2008  May 11, 2011
Printed
Page 334
dumb questions, central column, bottom question

at the lower end of the answer replace:
"...you want string that 10 inches..."
with:
"...you want a string that is 10 inches..."

Anonymous  Sep 24, 2008  May 11, 2011
Printed
Page 364
second row in the text

replace:
"...and groom are distriuted."
with:
"...and groom are distributed."

Anonymous  Sep 24, 2008  May 11, 2011
Printed
Page 378
2n Dumb Question

In the answer to the second question replace:
"...because it make a difference..."
with:
"...because it makes a difference..."

Anonymous  Sep 24, 2008  May 11, 2011
Printed
Page 389, 398, 411
see description

When approximating the Binomial Distribution using the Normal Distribution, should it be "nq > 5", or "npq > 5"? There appears to be a discrepancy between pages.

Pg. 389... 3rd para + Vital Statistics (says nq > 5)
Pg. 398... 1st para in last A of Q&A (says nq > 5)
Pg. 411... Exercise Soln under Condition column for Situation "Normal approximation of X, X ~ B(n,p)" (says npq > 5)

Note from the Author or Editor:
Page 411 5th condition needs to be changed to say nq > 5 instead of npq > 5.

Anonymous  Dec 29, 2008  May 11, 2011
Printed
Page 399
Pool puzzle

for each dscrete probability -> for each discrete probability

Anonymous  Jan 05, 2009  May 11, 2011
Printed
Page 402
excercise solution

We said that X~B(40,0.25), so n=40, p=0.25 and q=0.75
this means that Variance=npq=40*0.25*0.75=7.5
so we can approximate X distribution as: X~N(10,7.5).

the standard score for x=29.5 is:

29.5 - 10
z=-------------=7.1
sqrt(7.5)

Note from the Author or Editor:
The solution on page 402 needs to be changed as follows:
--------------------------------------------------------

If X is the number of questions we get right, then we want to find P(X >= 30) where X ~ B(40, 0.25).

As np and nq are both greater than 5, it's appropriate for us to use the normal distribution to approximate this probability. np = 10 and npq = 7.5, which means we need to find P(X > 29.5) where X ~ N(10, 7.5).

Let's start by finding the standard score.

z = x - &#956;
-----
&#963;

= 29.5 - 10
---------
sqrt(7.5)

= 19.5
----
2.74

= 7.1

Looking up 7.116 in probability tables gives is a probability that's very close to 1. This means that

P(X > 29.5) = 1 - 1
= 0

Thought bubble:
---------------
The first sentence of the thought bubble should read "So, looks like you've got practically no chance of winning that swivel chair."

Anonymous  Sep 24, 2008  May 11, 2011
Printed
Page 407

"the binominal" should be changed to "the Poisson"

Anonymous  Sep 30, 2008  May 11, 2011
Printed
Page 422
2nd paragraph

Typo - "reseraching" should be "researching"

Anonymous  Feb 09, 2009  May 11, 2011
Printed
Page 636-pp639
typo error in Exercise Solution

According to pp636 the exercise has 9 data points, with radiation exposures 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7.
But the solution on pp 638-639 has only 7 data points - it is missing the 3 and 3.5.

Note from the Author or Editor:
The data table on page 636 needs to be changed to reflect the data on page 638.

Anonymous  Nov 19, 2008  May 11, 2011