Posts Tagged ‘ confidence intervals ’

Confidence Regions for Regression Coefficients

September 16, 2012
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Confidence Regions for Regression Coefficients

Let’s consider the usual linear regression model, with the full set of assumptions:                     y = Xβ + ε ;    ε ~ N , (1)where X is a non-random (n × k) mat...

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Plotting 95% Confidence Bands in R

July 26, 2012
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Plotting 95% Confidence Bands in R

I am comparing estimates from subject-specific GLMMs and population-average GEE models as part of a publication I am working on. As part of this, I want to visualize predictions of each type of model including 95% confidence bands. First I had to ma...

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Plotting 95% Confidence Bands in R

July 24, 2012
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Plotting 95% Confidence Bands in R

I am comparing estimates from subject-specific GLMMs and population-average GEE models as part of a publication I am working on. As part of this, I want to visualize predictions of each type of model including 95% confidence bands. First I … Continue reading →

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Example 9.14: confidence intervals for logistic regression models

November 15, 2011
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Example 9.14: confidence intervals for logistic regression models

Recently a student asked about the difference between confint() and confint.default() functions, both available in the MASS library to calculate confidence intervals from logistic regression models. The following example demonstrates that they yield d...

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Plotting grouped data vs time with error bars in R

October 31, 2011
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Plotting grouped data vs time with error bars in R

This is my first blog since joining R-bloggers. I’m quite excited to be part of this group and apologize if I bore any experienced R users with my basic blogs for learning R or offend programmers with my inefficient, sloppy … Continue reading →

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Plotting grouped data vs time with error bars in R

October 31, 2011
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Plotting grouped data vs time with error bars in R

This is my first blog since joiningR-bloggers. I’m quite excited to be part of this group and apologize if I boreany experienced R users with my basic blogs for learning R or offendprogrammers with my inefficient, sloppy coding. Hopefully writing for...

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Test Difference between Two Proportions & Plot Confidence Intervals

August 11, 2011
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Test Difference between Two Proportions & Plot Confidence Intervals

..an illustrative example for testing proportions and presenting the results.the data: number of indigenous and alien plant species with and without vegetative reproduction. Hypothesis: The proportion of species with vegetative reproduction is differen...

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Bayesian Confidence Intervals: Obama’s ‘That’-Addition and Informality

May 1, 2011
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Bayesian Confidence Intervals: Obama’s ‘That’-Addition and Informality

No “That” Left Behind? I came across a post on Language Log last week giving some evidence that Obama tends to add that to the prepared version of his speeches. For example, in a recent speech at George Washington University, … Continue reading →

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Fit Sigmoid Curve with Confidence Intervals

April 28, 2011
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Fit Sigmoid Curve with Confidence Intervals

Sigmoid curve fitting for transpiration measurements from porometer at different water potentials (pressure):Read more »

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Survival paper (update)

January 13, 2011
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Survival paper (update)

In a recent post, I discussed some  statistical consultancy I was involved with. I was quite proud of the nice ggplot2 graphics I had created. The graphs nicely summarised the main points of the paper: I’ve just had the proofs from the journal, and next to the graphs there is the following note: It is

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