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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
V. Statistical Inference: Estimating population parameters
and testing hypotheses (continued)
B. Tests of significance
7.
Test for the slope of a least-squares regression line
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| Essential Question:
How can you express the
uncertainty in the slope of a line? |
Ch. 14.1 Inference for Regression
- State the 2 inferences drawn when
using regression data. (slope & intercept)
- State the assumptions for
regression inference.
- for any x value, y-data is normally distributed
- for any x value, the y-data's standard deviation is the same
- the means of the y-data distribution at any value of x form a
straight line relationship: my =
a + bx
- Calculate the standard error of the least squares regression
line.
s = [S(y - ŷ)2
/ (n-2)]1/2
- Calculate the standard error of the slope.
SEb = s/[(S(x -`x)1/2]
Homefun --
-- Read section 14.1, prob. 14.5, 14.7, 14.9
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- Lesson 1
- Key Concept: How to
evaluate the slope obtained in a regression
analysis
Interactive
Discussion: Why is the slope of the line is a big deal. It often
has physical meaning
Famous slopes Mr. R
has known:
2-person teams: Using
data from an Einstein's photoelectric experiment find plank's
constant using regression analysis in Minitab. Calculate a
confidence interval on the slope of the line (plank's constant).
Compare this technique to IB error analysis techniques.
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| Essential Question:
How can spot a meaningless
regression anaysis? |
Evaluating
Regression Results
- Generate a confidence interval for the slope. (n-2 degrees of
freedom)
b± t*SEb
- Calculate the t-value for a hypothesis test
of the slope Ho: b
= 0. (n-2 degrees of freedom)
t = b / SEb
- Perform a significance test for the slope of a
least squares regression line.
- Correctly perform least squares regression
using Minitab.
- Correctly interpret least squares regression
computer output (such as from Minitab).
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- Lesson 2
- Key Concept: Spotting a
meaningless regression analysis
Interactive
Discussion: Objectives. While it's possible to spot a
meaningless regression analysis, it's not possible to tell for
certain if an analysis is meaningful.
2-person teams: (see the stats investigation below)
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| Stats
Investigation: How to Spot a
Meaningless Regression Analysis - time approx 2 class
periods (individual work) |
Purpose: Determine if a regression analysis using random
numbers that has a high r-square value can be detected with
hypothesis tests on the slope and intercept.
Instructions: Remember the
stats investigation you did earlier in which you determined
that even random data can produce a high r-square value.
Redo the regression/correlation analysis in Minitab on the 4
sets of data you saved and interpret the results. Be
sure to take all the recommended steps for producing a
statistically significant regression analysis.
Questions /Conclusions:
- Based on your data, could you spot
randomness with the hypothesis tests on the slope and
intercept of the regression equation.
Explain
- Outline all the steps which should be taken to produce
a regression/correlation analysis with the best chance of
being meaningful.
- Can a thorough statistical analysis of
bivariate data, by itself
fully establish that a regression result is meaningful?
Explain
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| Essential Question:
How can we evaluate or include
possible lurking variable in a
regression anaysis? |
Ch. 14
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Perform multiple linear
regression analysis using Minitab and correctly interpret the
regression equation, R2, and the hypothesis tests.
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State would you plot and interpret
residuals for a multiple regression analysis.
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- Lesson 3
- Key Concept: Control of variables in a study
Interactive Discussion:
Review the following from
chap 5:
- Be as one with the three basic principles of
experimental design.
- Control - effects of lurking
variables
- Randomization - prevents sampling
bias
- Replication - collect numerous data
points
2-person teams: Perform a multiple
linear regression analysis on the SAT data used earlier in the year.
Compare the results with those obtained earlier using 2 variable
regression analysis.
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