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AP Statistics Standards
I. Exploring Data:
Observing patterns and departures from patterns (continued)
D. Exploring bivariate data
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Transformations to achieve
linearity: logarithmic and power transformations
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Objectives |
| Essential Question:
Is everything we'd like to study
and model linear? |
Chapter 4 : 2 Variable Data Continued
Modeling Non-Linear Data
- Explain how both power and exponential
functions can be transformed into linear forms.
- Give examples where an exponential regression model would
be appropriate.
Growth or decay situations (response variable multiplied by a fixed
amount in each time interval) such as:
- bacteria population growth
- the doubling of computer power
- radioactive decay (decay of a population of atoms)
- Give examples where a power regression model would be
appropriate.
Scaling problems:
- Volume & mass scale with the cube of the scaling factor
- Area scales with the square of the scaling factor
- Explain how to determine if an non-linear model is
appropriate.
- theoretical basis such as 2 & 3 above
- random residuals
- Explain why a model should not be selected on
the basis of optimizing r-square.
- Perform linear regression on transformed data
and convert the results to the appropriate power or exponential equations.
Homefun: Read section 4.1; prob. 4.1,
4.4, 4.13, 4.17
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Activities |
- Lesson 1
- Key Concept:
Transforms
- Purpose:
Create a linear plot from nonlinear data
Interactive Discussion:
Objectives. Explain the terms concaved upward and downward. Review
logarithms and explain why the common transforms use them.
Demo: Use
Fathom software to show that any nonlinear data set can
be transformed if the equation is known.
Seat Work: work example problems
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| Essential Question:
What is the most common form of
extrapolation? |
Interpreting Correlation and
Regression
- Decry the evils
of extrapolation.
- Identify
possible lurking variable. (An important variable which is not included
in the study.)
- Name the most common lurking variable.
(time)
- State the pitfall of using averaged
data. (The results look artificially good.)
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- Lesson 2
- Key Concept:
Extrapolation and lurking variables
- Purpose: Understand how
conclusions drawn from data can be disastrously wrong
Interactive Discussion:
Objectives. Explain real growth curves--usually sigmoidal.
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| Essential Question:
Can we ever be completely sure
that causation exists? |
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Causation |
| In other words, is the
association between the x and y variables due to the x-variable
actually causing a response in the y-variable. |
- State 4 possible explanations for
getting a strong association based on regression/correlation analysis.
- Causation --Sometimes it's true
- Common response variables (affect both x & y
variables), example: rum and Methodist Ministers
are both affected by the common response variable of time.
- Confounding variables (affect the y variables
but not the x), example: The shaman chants an incantation and five
days later the patient gets well.
- Random chance
- Explain 4 ways that causation can be
established.
- multiple independent studies of different types
- Account for control or eliminate lurking
variables
- Turn the causative variable on and off
- Develop a plausible theory
Homefun: Read section 4.2; prob.
4.25, 4.27, 4.29
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- Lesson 2
- Key Concept:
Extrapolation and lurking variables
- Purpose: Understand how
conclusions drawn from data can be disastrously wrong
Interactive Discussion:
Objectives.
Video: use video on smoking
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AP Statistics Standards
I. Exploring Data:
Observing patterns and departures from patterns (continued)
E. Exploring categorical data
1. Frequency tables and bar charts
2. Marginal and joint frequencies for two-way tables
3. Conditional relative frequencies and association
4. Comparing distributions using bar charts
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| Essential Question:
Can data sets be added together
to obtain a larger sample size and hence more meaningful conclusion? |
Categorical Data
& Simpson's Paradox
- Create frequency tables for categorical data.
- Convert the above tables into bar charts.
- Use conditional distributions based on relative frequencies to establish
associations.
- Compare distributions using bar charts.
- Interpret 2-way tables.
- Interpret marginal distributions.
- 2 for each table, horizontal & vertical
- Histogram like
- Single variable only
- Calculate and interpret
conditional distributions
- Analyze data for
Simpson's paradox.
- Conclusions based on parts can be reversed when
considering the whole
- Conclusions based on parts is more likely to be
valid.
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State two conditions which must exist for
Simpson's Paradox to occur.
- One or more lurking variables
- Data from unequal sized groups being combined into a
single group.
- State how Simpson's paradox can be prevented.
- Avoid combining data from unequal groups into a
single study
- Identify and include lurking variables in the study
Homefun: Read
Simpsons's Paradox
- When Big Data Sets Go Bad
prob. 4.37, 4.39, 4.45
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- Lesson 2
- Key Concept:
Simpson's Paradox
- Purpose: Understand how
conclusions drawn from data can be disastrously wrong
Interactive Discussion:
Objectives. Work through hospital example of Simpson's paradox.
Individual work:
Work through Simpson's paradox
worksheet provided by teacher.
Use Titanic data to determine if the
class of one's ticket had an association with the chances of
survival.
Materials: Simpson's Paradox
Worksheet and Titanic data.
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