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Latin
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Latin/Greek Root Words
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(Statistics
connection) |
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AP Statistics Standards
IV. Statistical Inference: Confirming
models
A. Confidence intervals
IV. Statistical Inference: Confirming
models (continued)
B. Tests of significance
C. Special case of normally distributed
data
- t-distribution
- Single sample t procedures
- Two sample (independent and matched
pairs) t procedures
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| Essential Question:
How can we account for the greater
uncertainty of analyzing data when sample size is small and little
is known about the population? |
Ch 11
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State the 2 assumptions for drawing inferences
about a population mean when sigma is not known.
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Calculate standard error
of a statistic
(std
dev of sampling distr.) = s / ( n^.5 )
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Explain when a t statistic is used rather than
a z score.
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Calculate t statistics.
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State the degrees of freedom for a t test.
df = ( n-1 )
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Construct confidence intervals using the t statistic.
ME = t*
s
/ ( n0.5 )
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Perform one sample t-procedures:
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by hand (using the
calculator only for basic mathematics) using t-tables.
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by hand, using the
calculator only for basic mathematics and finding areas.
- tcdf (L,U,D)
- Lower
t-value
- Upper
t-
value
- Degrees
of Freedom
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μ
is the mean associated with
Ha
μo
is the mean associated with
Ho
Homefun
(formative/summative assessment): 11.7, 11.9, -- Read section
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- Lesson 1
- Key Concept: How is
t-Distribution used?
Warm up: What
conditions must be met to use a z-test?
Interactive Discussion:
Objectives.
What conditions must be met to
use a t-test and how does this differ from a z-test?
Assuming a t-test is called for, what
kinds of tests should be performed before using a t-test?
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| Essential Question:
What is the single most powerful
form of hypothesis testing and why? |
Matched Pairs Testing
(Spanish Camp)
- Apply the
t-test of significance to matched pairs (MP) situations.
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MP tests are 1 sample t-tests
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Ho:
μ = 0
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df = (number
of pairs - 1)
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Be aware: you
must establish that the population is approximately normally
distributed.
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How to
Establish That a Population is Normally Distributed
Box Plot
- symmetrical, box width smaller than a whisker's
width
Normal
Quantile Plot - straight line |
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Explain what is meant by a
robust test or confidence interval. p-value
or confidence interval changes little if assumptions are violated.
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Be as one with the
information in the "using t procedures" box on p.636.
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Be aware that outliers are
very harmful to the t-test. Making a modified
box plot of the data in order to look for outliers is a very good
idea.
Homefun
(formative/summative
assessment): 11.13,
11.17, 11.21, 11.26
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- Lesson 2
- Key Concept: How are Matched
Pairs t-test used.
Warm up questions (individuals):
- What two assumptions must be met
to use a t-test?
- How do you know you have normally
distributed data?
- What step must you take before using a t-test
of any kind?
Interactive Discussion:
Set up confidence intervals and hypothesis tests for matched pairs.
Problem Solving (Teams of
two): Make a hypothesis test with matched pairs for a pre and
post test situation--Spanish Camp
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| Essential Question:
How can you determine if 2
populations differ if at the start you have no information? |
Ch 11
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State the assumptions made
for two-sample tests. (p. 650)
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SRS
used for generating the
sample
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independent
- matched pairs violate independence
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normally
distributed
population
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Create confidence intervals
and hypothesis test using two sample t procedures assuming that the
sigmas of the two populations are unequal. This is the most
conservative assumption.
Ho:
μ1 - μ2
= 0 but can also
be written, Ho:
μ1 = μ2
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Test Statistic for
Hypothesis Testing |
Margin of Error
for Confidence Interval |
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t = |
(xbar1 - xbar2)
- 0
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(s12/n1
+ s22/n2)0.5 |
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| ME =
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t* (s12/n1
+ s22/n2)
0.5 |
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Create confidence intervals
and hypothesis test using two sample t procedures and the most
conservative method of determining df.
df = (the lower of n1 -1
or n2 - 1)
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Be aware of the more
accurate way to calculate df as shown on page 659.
This is the method used in the TI-83
calculator
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Perform two sample
hypothesis t-procedures on the TI-83.
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State the key assumption
required for using the pooled two-sample t-procedures.
This is the method is an option in the TI-83
calculator.
The sigmas of the two populations are
the same
Homefun
(formative/summative assessment): 11.33,
11.35, 11.37, 11.49:
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Lesson 3
Essential Question: How
are two sample
t-procedures -- no assumption made about the standard deviation
being equal(p.624)--used?
Warm up questions (Individual):
- What two types of tools are used for
inference?
- What type of distribution is used for making inferences?
Interactive Discussion:
Set up a hypothesis test for two samples and point out how
it differs from Z-test
Problem Solving (Teams of
two): Make a hypothesis test with 2 sample and matched pairs for
a pre and post test situation--return to the Spanish Camp data.
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