INVESTIGATING STATISTICAL CONCEPTS,
APPLICATIONS, AND
METHODS
Last updated January 21
(these errata reflect changes that were not made
in the
preliminary edition)
p. 5,
paragraph after (h)
insert
“the” between “that is” and “risks”
p. 6, study
conclusions
insert
“of” between “a difference in the risk” and
“airway”
p. 14, question (l)
Instead of asking if this is an estimate of the percentage that "are smokers," should ask if this is an estimate of the percentage that "have lung cancer."
p. 15,
definition of cohort study
Current definition
is a little simplified. The subjects do
not have to be “selected according to” the explanatory variable
(though that is one example), but the explanatory variable should be
observable
at the start of the study and the outcomes occur “naturally”
(chosen by the subjects, not by the researchers). In
a prospective cohort study, the subjects
are then followed over a period of time and the response variable then
observed.
p. 18, question (s) – as labeled
Might want to reverse order of intermediate risk calculations
Note: Questions
(q)(s) can be relabeled and you might want to say “calculate” for
the first one and then “compare this” for the next two.
p. 19, discussion
the last relative risk calculation should be 1.54 not 1.44
p. 32, before
(f)
You might want to
insert “Weighted Average” as a new section heading
p. 3334,
questions (i) and (k)
Replace with
“Is the overall acceptance rate for women equal to the average of their
acceptance rates in each program?”
This will also affect the conclusion statement.
The easiest fix is to delete the first
sentence.
You may prefer to
replace these pages with these.
p. 37,
missing figure
p. 54, last
lines
change the
inequalities on the right hand side to less than or equal to
inequalities.
p. 60, before
question (i)
Discussion and
confidence interval formula should be removed
p. 65,
introduction
Delete second sentence and change paragraph to: “In the previous investigation there were only 15 outcomes in our sample space and it was feasible to list each outcome. The 2004 U.S. Senate consists of 86 men and 14 women. Suppose that they are randomly assigned to a subcommittee of 5 members (and a second group of 95 nonsubcommittee members). Let the random variable X represent the number of women on the subcommittee.”
p. 65, before
part (d)
change
“interesting” to “interested”
p. 67, part
(k)
the last command
should read
MTB> plot c2*c1;
SUBC> project.
p. 69,
practice 120(i)
change
“bottom” to “button”
p. 73,
calculation details
we intended for the
calculation details to be displayed
In the above table, we could have found the pvalue as the probability of obtaining 8 or more successes in Group B:
P(Y>8)=
Or the probability of 9 or more “nonthreshold beaters” in Group A:
P(Z>9)=
p. 78, practice
problem 123
you should probably
clarify that the files were assigned “gender” at random
p. 83
you will want to
number the figures 16 for easier reference
p. 92, 2^{nd}
bullet
They need to click OK
after they select the With Groups option to move to the next window.
p. 95, practice
problem 22
Consider asking
students to pick one comparison in (a) and in (b) and asking if the
wooden vs.
steel comparison is ask they expected.
p. 96, part
(b)
After choosing the
“Multiple Y’s, Simple” option, will need to click OK to move
to the next window.
p. 101, Histogram of class A can be
rescaled so the
vertical axis matches that of all the other graphs.
These are the
numerical values:

Jan 
Feb 
Mar 
Apr 
May 
Jun 
Jul 
Aug 
Sep 
Oct 
Nov 
Dec 
Raleigh 
39 
42 
50 
59 
67 
74 
78 
77 
71 
60 
51 
43 
SF 
49 
52 
53 
56 
58 
62 
63 
64 
65 
61 
55 
49 
p. 104,
practice 24(b)
The initial number
of intervals is 12, not 14.
p. 109
practice 27
For the ACT scores,
consider changing the parameters to a mean of 21 and a standard
deviation of
5. Since the ACT max composite score is
36, can change Jeff’s score to 28.
p. 110, part
(a)
will need to make
sure they do not type in the quotation marks
p. 112,
question (l)
change to “and
examine numerical and graphical summaries to analyze the distribution
of the
price differences between the two years.
Write a paragraph summarizing how the years compare.”
p. 119, part
(q)
By
“generic,” we mean for a generic data set with n=8
values.
p. 127, part
(l)
may need to change
first Minitab line to: MTB>
let c8 = (c6>=15.92)
p. 128, figure of t distribution
can be
improved:
p. 131, part
(a)
Can also ask them to
calculate the mean and standard deviation as part of their numerical
summaries
as well as will need that information later.
p. 133,
practice 213
need to reletter
the questions
p. 150,
question (a)
Have them describe
the sampling distribution in words (not the shape, center, and spread)
p. 160, practice 310
Could consider using
n=20 rather than n=100
p. 164 figure
The spikes at 22 and above should be highlighted
p. 166,
investigation 36
replace with this
p. 174, part
(u)
need to reletter
(t)(bb), including on p. 175 referring back to
new part (x)
p. 176
Change title to
“Inverse Cumulative Probabilities”
The Minitab screen
capture should refer to 10 as the number of trials
p. 194, 198
answers will vary slightly depending on decimal
expression
of 2/3 used.
p. 197
need to reletter
(d)(g) including in new (e) refer back to (d)
p. 202, part
(c)
use 1000 different sessions
instead of 200
bad page break
between p. 202 and p. 203
p. 204, part
(o)
Will click Count
instead of Calculate
p. 205, part
(r)
change number of
samples to 1000
p. 207 reletter
second part
(y) as part (z)
p. 214, part
(f)
In Hint, should use Stat
menu, not Calc menu
p. 240, part
(o)
Use a height of 152
instead of 151.8
p. 246,
practice 49, part (a)
change
“of” to “or” after “Minitab output”
p. 249250,
bad page break
p. 253, figure
q is
playing the
role of p
p. 254, part
(g)
use 50% instead of
75%
p. 265, figures
.583 should be .584 and .746 should be .75
p. 266, part
(k) should be part (m)
last paragraph:
delete “in” after “the same as those made”
p. 2667
Some additional
practice problems are available here
p. 268, part
(i)
pi should be p
p. 269
need to reletter
p. 270
Under the first set
of technical conditions, delete the parenthetical remark
p. 271,
practice 415
Parts (a) and (b)
should have the same confidence level
p. 273, part (i),
considering adding Hint: What is true about their
p. 292, CI
box
change “fs”
if “if”
p. 300, part
(t)
need square bracket
at end.
In screen capture of
Test of Significance Calculator, need mean = 195.88
p. 301 study
conclusions, paragraph 3
The 90% confidence
interval for m is (188.9, 202.8) and the 90% prediction interval
is (160.51, 231.25).
p. 308, first
line
need space in
“and the”
p. 309, part
(d)
change “from
this population” to “from this sample”
p. 313, part
(m)
delete this question
as every student has the same sample
p. 317,
practice problem
Should be 427, not
426
p. 319, table
could add hypergeometric
distribution in addition to binomial
distribution for the case the CLT does not apply
p. 321, The
observed number of responses in 2002 should be 591 instead of 587
p. 323, we
assume phat1 is for 1998 and phat2 is for 2002
p. 325, study
conclusion
delete second
sentence about zprocedures
p. 327, The
observed number of responses in 2002 should be 591 instead of 587
p. 329, part
(l), compare back to the interval in (k) instead (95%)
Study Conclusions:
When using 591, the onesided pvalue will be .051 and the 90%
confidence
interval is essentially 0%7.2%.
p. 347, page
reference
page 56 should be
page 326
p. 360,
practice 513
should refer to
practice 331 (p. 220) not investigation
313
p. 372, table notation
log odds ratio formulas should use
p. 377, in
first full paragraph, line 6
“excepted”
should be “expected”
p. 378,
probability fact
could replace the condition
of at least 20% of the expected counts with the average expected count
should
be at least 5
p. 3869,
header is off
p. 391, part (e) graphs
crutches is misspelled in both graphs
p. 393, missing formulas
p. 399, study conclusions
F should be 29.23
p. 405, figures
the quadrant labels are missing
p. 406, part (e)
The bars are missing on and (or delete the word “average” in each definition)
p. 410, part (a)
Another version of the applet is at http://www.rossmanchance.com/applets/GuessCorrelation/GuessCorrelation.html (this is the version that the http://www.rossmanchance.com/iscam/files page refers to.
In this applet, once the Enter button is pressed, the true correlation value appears. Below is a screen capture of this applet:
p. 414, scatterplot
The correlation coefficient (r = .711) is not displayed
p. 429
Sentences are repeated from bottom p. 428.