1
STA2023 – Exam 3 Outline (Chapters 18a  22)
The following is a checklist of important points covered in chapters 18a22.
You should use this outline as a
relatively comprehensive list of the major points of inferential statistics.
In addition to this review, look over
the online quizzes, the lab, and the inclass handouts/activities
You need to bring a graphing calculator with you to the exam.
Similar to the previous exams,
you will be
allowed a 3x5 index card for this exam (one side only).
There are several formulas involved in this work
(see the attached page) – write these formulas on the index card (they will NOT be provided on the exam).
The ZTable will be provided.
Chapter 18a

Be able to apply the NAB for the distribution of sample proportions (
^
p
values

).
The exact distribution of
^
p
values

is Binomial (a discrete distribution).
However, if certain conditions are met (pages 461462)
we can approximate the distribution of
^
p
values

with a Normal model (a continuous distribution).
^
p
p
μ
=
^
p
p q
n
σ
⋅
=

Know how to calculate probabilities using the NAB. Remember that the area under a Normal curve
represents a probability.
Example:
Find P(
^
0.37
p
>
)
Chapters 1922

Know that every confidence interval always follows the form: (point estimate
±
ME)

Know how to use the confidence interval formula to find a 90%, 95%, or 99% confidence interval for p
^
p
±
(z*)
.
^
^
p
q
n
⋅
where
z* for a 90% C.I. =
1.645
;
z* for a 95% C.I. =
1.96
;
z* for a 99% C.I. =
2.576

Understand that “95% confidence” means that, if many samples of size
n
were collected and 95%
confidence intervals were generated for each of those samples, 95% of the resulting confidence intervals
would contain the true value of the parameter being estimated and 5% would not.

How do you find the width of a confidence interval?
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 Spring '08
 Ripol
 Statistics, Inferential Statistics, 10%, Statistical hypothesis testing, 1%, 5%, 8.2%

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