Name:___________________________
Date:____________________
Labouré College
Essentials of Statistics
MAT 3410
Chapter 8 Quiz Prep
Howard Sesso and colleagues studied a population of male physicians in the U.S. to
assess the prevalence of cardiovascular risk factors.
Sesso et al. found that, among male physicians in the U.S. aged 60 years and younger,
systolic blood pressure (SBP, reported in mmHg) was normally distributed, with:

ϭ = 9.2
Here are a few scores from the z-table:
Level of Confidence (c)
0.90 or 90%
0.95, or 95%
0.98, or 98%
0.99, or 99%
Critical Value z
1.645
1.96
2.33
2.58
Sesso, H. D., Stampfer, M. J., Rosner, B., Hennekens, C. H., Gaziano, J. M., Manson, J. E., & Glynn, R.
J. (2000). Systolic and diastolic blood pressure, pulse pressure, and mean arterial pressure as predictors
of cardiovascular disease risk in men. Hypertension, 36(5), 801-807.
Instructions: Answer the questions below based on the parameter listed above from
the Sesso article. Note: You do not need a z-table for this quiz (all z scores needed are
listed above). However, you will need a t-table for this quiz. Make sure you look up this
table in your text, or download it from the Resources tab on eLearning.
Round calculations to 1-digit after the decimal.
1.
You work at a large health system in the United States. Recently, several male
physicians under the age of 60 have expressed concern to you about their blood
pressure. You decide to use the ϭ from the Sesso article to try to estimate μ in
this population (male physicians under 60 at your workplace). You take a
random sample of 9 male physicians under the age of 60 and measure their
SBP. Here are the results you get:
102
144
120
112
108
132
150
162
145
Compute the mean (x-bar) for this sample. Round to 1-digit after the decimal. (1
point)
2.
You decide to find the 95% confidence interval for the μ using this sample of 9
male physicians. Fill in the blanks below about this confidence interval.
2a.
With respect to your sample, what is the value of n? (1 point)
2b.
What is the value of x-bar that the confidence interval will be centered
around? (1 point)
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Name:___________________________
3.
4.
Date:____________________
2c.
For your 95% confidence interval, what is the value of ϭ? (1 point)
2d.
For your 95% confidence interval, what is the value of zc? (1 point)
2e.
For your 95% confidence interval, what is the margin of error? Round to 1digit after the decimal (. (1 point)
2f.
State the 95% confidence interval here. Round each limit to 1-digit after
the decimal (2 points):
2g.
After making this interval, what are you 95% confident about? (Circle one
answer, 1 point)
a.
I am 95% confident that the true μ falls into the range of my 95%
confidence interval.
b.
I am 95% confident that the true ϭ falls into the range of my 95%
confidence interval.
c.
I am 95% confident that my sample is not biased.
d.
I am 95% confident that SBP is normally distributed.
Find the sample size necessary for a 95% confidence interval with the maximum
margin of error = 3. Enter the information from your calculation below.
3a.
For your calculation, what is the value of zc? (1 point)
3b.
For your calculation, what is the value of ϭ? (1 point)
3c.
For your calculation, what is the value of your margin of error?
(1 point)
3d.
How many male physicians <60 years old from the U.S. are required in
order to have a 95% confidence interval with a maximum margin of error =
3 that estimate μ? Remember to always round up if you get a fraction to
make sure that enough people are recruited for the study. (1 point)?
You know that female physicians under age 60 are also at high risk for
cardiovascular disease. Unfortunately, the Sesso article only measured men, so
you do not have a ϭ to use. Instead, you take an SBP reading from a random
sample of 9 female physicians under 60 at your workplace and get the following
results:

x-bar = 120.2 mmHg

s = 8.6 mmHg
You decide to estimate the μ of this population with a 95% confidence interval,
but you must use s to estimate ϭ. (Questions begin on next page.)
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©Copyright Monika Maya Wahi 2015
Name:___________________________
4a.
Date:____________________
Why are you required to use the t-table on this question instead of the ztable? (Circle one answer, 1 point)
a.
Because the Sesso article is biased since it did not include women.
b.
Because SBP is not normally distributed.
c.
Because the ϭ is unknown, and we have a small sample size
(<500).
d.
Because the z-table does not have a probability for a 95%
confidence interval, but the t-table does.
4b.
With respect to your confidence interval equation, what is the value of n?
(1 point)
4c.
With respect to your confidence interval equation, what is the value of the
degrees of freedom ? (1 point)
4d.
With respect to your confidence interval equation, what is the value of xbar? (1 point)
4e.
With respect to your confidence interval equation, what is the value of s?
(1 point)
4f.
With respect to your confidence interval equation, what is the value of tc?
(1 point)
4g.
For your 95% confidence interval, what is the margin of error? Round to 1digit after the decimal (1 point)
4h.
State the 95% confidence interval here. Round each limit to 1-digit after
the decimal (2 points):
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©Copyright Monika Maya Wahi 2015