NGR 7848 Fundamentals of Statistics for Clinicians Ho.docx

NGR 7848: Fundamentals of Statistics for Clinicians
Homework #3
Student Name: __________________________
1. Assume that you want to calculate a confidence interval for a
mean (i.e. a continuous variable). Refer to the appendix tables
in
your textbook, and identify the correct value to be used for the
calculation (i.e. from either the t or z distribution) (5 points)
N
Desired
Confidence Interval
t or z distribution
(specify which one)
Correct
t or z Value
16 95% _____ 2.131

22 90% _____ 1.721
28 99% _____ 2.771
64 95% _____ 1.96
128 90% _____ 1.645
2. From the information below, calculate the desired confidence
for a one sample continuous variable (mean systolic blood
pressure). Show your work. (5 points)
Parameter: Mean systolic blood pressure
Sample N: 420
Sample Mean: 132.8
Sample SD: 17.4
Confidence Level: 95% Z value: ________ or t value:
_________
Answer:
_____________________________________________________
____________
3. Using your notes from class, repeat this same calculation in
SPSS. Make sure to paste your output (i.e. the 95% confidence
interval) below to verify your results for question #2. (5 points)
Parameter: Mean systolic blood pressure

Sample N: 420
Sample Mean: 132.8
Sample SD: 17.4
Confidence Level: 95%
4. For a one sample dichotomous outcome, calculate the desired
confidence interval for the proportion of the population with
hypertension. Show your work. (5 points)
Parameter: Proportion of population with diabetes
Sample N: 194
Sample Proportion: (16 / 194) = _________
Confidence Level: 90% Z value: __________
90% Confidence Interval:
________________________________________
5. For a two sample continuous outcome, independent groups,
calculate the desired confidence interval for the mean difference
in

resting heart rate (beats per minute) between smokers and non-
smokers. Show your work. (5 points)
Parameter: Mean difference in resting heart rate between a
sample of smokers and non-smokers
Xsmokers = 76.4; n1 = 58; s1 = 9.2
Xnon-smokers = 71.8; n2 = 210; s2 = 8.4
6. Using your notes from class, use SPSS to calculate a 95%
confidence interval for the mean difference in resting heart rate
by
smoking status. Make sure to paste your output below. (5
points)
Parameter: Mean difference in resting heart rate between a
sample of smokers and non-smokers
Xsmokers = 76.4; n1 = 58; s1 = 9.2
Xnon-smokers = 71.8; n2 = 210; s2 = 8.4
7. Compute the desired confidence interval for the risk ratio
comparing the risk of memory problems among
statin users versus non-statin users. Show your work..
Memory OK Memory Problems Total Incidence
Statin user 232 32 264 p1 =

Non-statin user 949 88 1,037 p2 =
Total 1,181 120 1,301
among statin users
(exposed) versus non-statin users (not exposed)
Confidence Level: 95% Z value: _______
8. One Sample Continuous Outcome: Compare historical
“control” mean (µ0) from a population to a “sample” mean.
Assume total LDL cholesterol levels in a sample of adults in
Tampa in 2010 were (n=558, X = 132.8, s = 21.4). Evaluate if
LDL cholesterol levels in Tampa are higher than the national
average in 2010 (127.5)
1) Set up hypothesis and determine the level of statistical
significance (including 1 versus 2-sided hypothesis).
H0: µ = ______
H1: µ ______ 1-sided or 2 sided? _______________
α = 0.05

2) Select the appropriate test statistic.
Use t or use z? ______________
3) Set up the decision rule (Table 1c).
Reject H0 if ______________________________
4) Compute the test statistic:
5) Conclusion: _____________________________________
9. One Sample Dichotomous Outcome: Compare historical
“control” proportion (p) from a population to a “sample”
proportion.
Assume the prevalence of diabetes in a Tampa-based study of
adults in 2004 (n=820, p = 70 / 820 = 0.0854 is lower than
a national (“historical”) report in the year 2004 (p0 = 0.1144).
H0: p = ______

H1: p ______ 1-sided or 2 sided? _______________
α = 0.05
2) Select the appropriate test statistic (assume z – large
sample).
Use t or use z? ______________
3) Set up the decision rule (Table 1c).
Reject H0 if ______________________________
5) Conclusion: _____________________________________
10. One Sample Categorical/Ordinal Outcome:
Compare proportions of categories of weekly alcohol
consumption among a sample of graduate USF students to a
national
sample (historical)

H0: _______________________________ H1:
___________________________ 1-sided or 2 sided? ______
2) Select the appropriate test statistic.
3) Set up the decision rule.
d.f. = ______________________________ α = 0.05
Refer table Table 3 in appendix: critical value = _______
Reject H0 if χ
2 ___________________
5) Conclusion: _____________________________________
National Sample
0-1 days 2-4 days 5-7 days Total
n 1,600 2,650 750 5,000
p 0.32 0.53 0.15 1.0
0-1 days 2-4 days 5-7 days Total
n 140 182 58 380
p _________ _______ _______ 1.0

e _________ _______ _______
USF
Fill in cells above
11. One Sample Matched Continuous Outcome:
Assess whether mean total cholesterol levels in 12 trial subjects
are lower after treatment with a lipid lowering drug.
ID Baseline 2 Weeks Difference
1 288 212 _________
2 264 182 _________
3 328 256 _________
4 290 263 _________
5 348 228 _________
6 276 174 _________
7 391 248 _________
8 288 183 _________
9 264 248 _________
10 311 201 _________

11 322 212 _________
12 300 194 _________
1) Fill in the difference column subtracting the 2-week value
minus the
baseline value
2) Compute the mean of the difference scores (show your work)
3) Compute the standard deviation (s) of the difference scores
(show
your work)
significance (including 1 versus 2-sided hypothesis). α = 0.05
H0: _______________________________ H1:
___________________________ 1-sided or 2 sided? ______
2) Select the appropriate test statistic z or t ____________
3) Set up the decision rule (look up z or t value).
Reject H0 if: ______________________________

5) Conclusion
_______________________________________________
12. Two Sample, Independent Groups, Continuous Outcome:
From the HEART SCORE study, compare mean body mass
index (BMI) between men and women (α = 0.05)
H0: _______________________________ H1:
___________________________ 1-sided or 2 sided? ______
2) Select the appropriate test statistic z or t ____________
3) Set up the decision rule
Reject H0 if: ______________________________

4) Compute the test statistic (show your work):
5) Conclusion
_______________________________________________
n X s
Men 164 29.74 5.112
Women 335 30.31 6.276
13. Two Sample, Independent Groups, Continuous Outcome:
From the HEART SCORE study, compare mean body mass
index (BMI) between men and women (α = 0.05)
Using SPSS and “Compare Means – Independent Sample T-test
procedure, compare mean body mass
index between men and women – paste your output below

14. Two Sample, Independent Groups, Dichotomous Outcome:
From the HEART SCORE study, compare the prevalence
(assumed incidence) of diabetes by gender (α = 0.05)
No diabetes Diabetes Total
Men 152 12 164 p1 = _________
Women 308 29 337 p2 = _________
(RD) (p1 – p2 = _______); Risk Ratio (RR) (p1 / p2 = _______)
H0: _______________________________ H1:
___________________________ 1-sided or 2 sided? ______
2) Select the appropriate test statistic
Reject H0 if: ______________________________

4) Compute the test statistic (show your work):
5) Conclusion
_______________________________________________
p = ______________ = __________
z =
_____________________________________________________
_____
15. Two Sample, Independent Groups, Dichotomous Outcome:
From the HEART SCORE study, compare the prevalence of
diabetes by gender (α = 0.05)
Using SPSS and “Descriptive Statistics – Crosstabs procedure”,
compare the prevalence of
diabetes by gender (chi-square test) – paste your output below.

16. More than two independent Groups, Continuous Outcome:
Body mass index by blood pressure classification (α = 0.05)
H0: _______________________________ H1:
___________________________ 1-sided or 2 sided? ______
2) Select the appropriate test statistic
Total N = n1 + n2 + n3 + n4 = __________________
df1 = k – 1 = ___________ df2 = N – k = ___________
Reject H0 if: _______________________
4) Compute the test statistic: F = _______ N = _________
Fill in entries below

5) Conclusion
_______________________________________________
Normal Pre-hypertensive Htn Stage I Htn Stage II
n1 = 88 n2 = 191 n3 = 139 n4 = 55
X1 = 28.42 X2 = 29.43 X3 = 30.75 X4 = 33.39
s = 5.372 s = 5.757 s = 5.885 s = 6.386
17. More than two independent Groups, Categorical Outcome:
Smoking status and exercise >3 times per week (α = 0.05)
H0: _______________________________ H1:
___________________________ 1-sided or 2 sided? ______
2) Select the appropriate test statistic: χ2
df = (r – 1)(c – 1) df = ________ From table 3, critical value
= ______ Reject H0 if: ______________

4) Compute the test statistic: Expected cell frequency (below)
= (row total x column total) / N
Smoking Status (Observed) Exercise < 3 times/week Exercise
>3 times/week Total
Current smoker 24 (________) 20 (________) 44 (1.0)
Former smoker 72 (________) 153 (________) 225 (1.0)
Never smoker 99 (________) 128 (________) 227 (1.0)
Total 195 (________) 301 (________) 496 (1.0)
Fill in the cells below
Smoking Status (Expected) Exercise < 3 times/week Exercise >3
times/week Total
Current smoker ______ ______ ______
Former smoker ______ ______ ______
Never smoker ______ ______ ______
Total 195 (________) 301 (________) 496
χ2 =
5) Conclusion
_______________________________________________

O r g a n i z e Y o u r S p e e c h
Organizing a speech is similar to writing an essay. Every essay
must have
an introductory paragraph, a body, and a concluding paragraph
A speech
has the same three divisions: an introduction, a body, and a
conclusion. T o
determine whether your ideas are clearly organized and easy to
follow, you
must consider the organization of each of these three parts of
your speech.
Organize Your Speech Introduction. Though usually brief, your
speech
introduction serves five vital functions. First, it focuses the
audience's atten-
tion on your message. You want to command their attention
with your first
words. How can you do this? Question your audience, amuse
them, arouse
their curiosity about your subject, or stimulate their
imaginations.
Second, your introduction should clarify your topic or your
purpose in
speaking. If your listeners are confused about your exact topic,
you limit
their ability to listen actively. To minimize any chances of this,
state your
purpose clearly in a well-worded sentence.
A third function of your introduction is to establish the
significance
of your topic or to explain your interest in it. Fourth, your
introduction

should help establish your credibility as a speaker on that topic.
Reveal
any special qualifications you have for speaking on the topic,
and use your
words, voice, and body to instill confidence in your listeners
that you have
prepared thoroughly. Finally, your introduction should highlight
or pre-
view the aspects of your subject that you will discuss in the
body. Well-
planned and well-delivered opening remarks will make the
audience want
to listen and will prepare them for what comes next. To check
the integrity
of your speech introduction, answer the following questions:
What are the parts of my introduction?
• What is my attention getter?
• What is my statement of purpose?
• What rationale do I provide for speaking about this topic?
• How do I establish my credibility to speak on this topic?
• What are the points I will cover in my speech?
Organize the Body of Your Speech. The body of your speech is
its
longest, most substantial scction. Though it follows your
introduction, you
should prepare the body of your speech first. Here you
introduce your
key ideas and support or explain each one. You should develop
only two
or three main ideas in a first speech, because you can more
easily develop

them within your time limit. Your audience will also more
easily grasp and
remember a few well-developed ideas. Restricting your main
points to a
few is particularly important in a first speech because it may be
the shortest
presentation you make during the semester or quarter.
Your organizational goal in the body is to structure your main
points
so clearly that they are both distinct and unmistakable to your
listeners.
T o help you do so, we recommend a four-step sequence—the "
4 S ' s " — f o r
organizing each of your main ideas. First, signpost each main
idea. Typical
signposts are numbers ( " f i r s t " or " o n e " ) and words such
as initially and
finally. Second, state the idea clearly. Third, support, or
explain, the idea;
this step will take you the most time. Finally, summarize the
idea before
moving to your next one. These four steps will help you
highlight and
develop each o f your main ideas in a logical, orderly way. The
following
questions and outline form should help you determine whether
the body o f
your speech is well organized:
Have I organized the body o f my speech clearly?
I. W h a t is m y first main idea?
A. What will 1 say about it?
B. H o w will I summarize it?

II. W h a t is m y second main idea?
A. W h a t will I say a b o u t it?
III. W h a t is my third main idea?
A. W h a t will I say about it?
Organize Your Speech Conclusion. Your speech conclusion is a
brief
final step with three main functions. The first is the summary, a
final review
of the main points you have covered. Summarizing may be as
simple as list-
ing the key ideas you discussed in the body of the speech. You
should not
introduce and develop any new ideas in the conclusion. When
you summa-
rize, you bring your speech to a logical close.
The conclusion's second function is to activate an audience
response by
letting your listeners know whether you want them to accept,
use, believe,
or act on the content of your speech. Whether your speech is
informative or
persuasive, you want the audience to have been involved with
your infor-
mation and ideas. This is your last opportunity to highlight what
you want
your listeners to take away from your speech.
Finally, your conclusion should provide your speech with a
strong sense
of Closure. T o do this, end on a positive, forceful note. You
can use many

h e r e t h a t r u s e d t 0 t h e audience's attention a
^ ^ a t i o ^ r ^ ^ r w f 7 d i e n T a m u s e t h e m > their
° U t a n d ely well w o r d e d Ask a n T ^ u * ^ ^ ^ h t
vour soeech cnnrl„«;nn. ^ Ask a n d answer these questions to
test
What are the parts o f my conclusion?
• What is my summary statement?
• What am I asking my audience to remember or do?
• What is my closing statement?
If you answer each of the questions we've posed so far, you
should have
an interesting, well-developed speech that is easy to follow.
Both your con-
tent and your organization are in good shape.
Up to this point, you have spent most of your time thinking
about the
speech and jotting down ideas. Now you have to word those
ideas and practice
getting them across to your audience through your vocal and
physical delivery.
Word Your Speech
Unless your instructor requests that you do so, avoid writing out
your first
speech word for word. Even though having the text of your
speech in front
of you may make you feel more secure, students who deliver
speeches from

manuscripts often suffer two consequences. One is that what
they say tends
to sound like writing rather than speech. In Chapter 12 we'll
examine some
of the important differences between oral and written styles.
A second problem is a lack of eye contact. Effective speakers
make eye
contact with their listeners. If you are reading, you can't do this.
Therefore,
if you have a choice, speak from just a few notes rather than
from a pre-
pared manuscript.
T h e language of your speech should be correct, clear, and
vivid. T o
illustrate this, assume that you have been assigned a practice
speech of
self-introduction early in the course. Assume, t o o , that you
have decided
to make your travels one of your main points. "I've traveled
quite a b i t " is
a vague, general statement. Without supporting materials, the
statement is
also superficial. Instead, suppose you said,
I've traveled quite a bit. I had lived in five states before I was in
middle school,
for example. When I was seven, my father worked in the
booming oil busi-
ness, and my family even got a chance to live in South America
for more
than a year. My brother and I went to an American school in the
tiny village
of Anaco, Venezuela; we were students 99 and 100 in a school
that taught

grades 1 through 8. Instruction in Spanish started in the first
grade, and by
the time we returned to the States, I was bilingual. I have vivid
memories of
picking mangoes and papayas off the trees, swimming outdoors
on Christmas
day, and having my youngest brother born in Venezuela.
T h e second statement is a great deal clearer and more vivid
than the
first. It begins with the general comment, but then amplifies it
with details.
T h e language is personal, conversational, and crisp. T h e
following ques-
tions should help you test the language of your speech:
• Does my speech sound conversational?
• D o I use language correctly?
• Will the language of my speech be clear to my listeners?
• Will the language of my speech be vivid for my listeners?

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