283 search results for "ANova"

Power Analysis for mixed-effect models in R

September 18, 2009
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Power Analysis for mixed-effect models in R

The power of a statistical test is the probability that a null hypothesis will be rejected when the alternative hypothesis is true. In lay terms, power is your ability to refine or "prove" your expectations from the data you collect. The most frequent...

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Power Analysis for mixed-effect models in R

September 18, 2009
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Power Analysis for mixed-effect models in R

The power of a statistical test is the probability that a null hypothesis will be rejected when the alternative hypothesis is true. In lay terms, power is your ability to refine or "prove" your expectations from the data you collect. The most frequent...

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Polynomial regression techniques

September 5, 2009
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Polynomial regression techniques

Suppose we want to create a polynomial that can approximate better the following dataset on the population of a certain Italian city over 10 years. The table summarizes the data:$$\begin{tabular}{|1|1|}\hline Year & Population\\ \hline 1959&4835\\ 1960&4970\\ 1961&5085\\ 1962&5160\\ 1963&5310\\ 1964&5260\\ 1965&5235\\ 1966&5255\\ 1967&5235\\ 1968&5210\\ 1969&5175\\ \hline \end{tabular}$$First we import the data into R:Year Population Now we create the dataframe...

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Polynomial regression techniques

September 5, 2009
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Polynomial regression techniques

Suppose we want to create a polynomial that can approximate better the following dataset on the population of a certain Italian city over 10 years. The table summarizes the data:$$\begin{tabular}{|1|1|}\hline Year & Population\\ \hline 1959&4835\\ 1960&4970\\ 1961&5085\\ 1962&5160\\ 1963&5310\\ 1964&5260\\ 1965&5235\\ 1966&5255\\ 1967&5235\\ 1968&5210\\ 1969&5175\\ \hline \end{tabular}$$First we import the data into R:Year Population Now we create the dataframe...

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Let’s All Go Down to the Barplot!

September 3, 2009
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Let’s All Go Down to the Barplot!

I’m back for another pean to ANOVA-loving experimental ecology. Barplots (or point-range plots – but which is better is a discussion for a different time) are the thing! And a friend of mine was recently asking me how to do a decent barplot with ggplot2 for data of moderate complexity (e.g., a 2-way ANOVA). So

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Analysis of Variance

September 1, 2009
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Analysis of Variance

In an experiment study, various treatments are applied to test subjects and the response data is gathered for analysis. A critical tool for carrying out the analysis is the Analysis of Variance (ANOVA). It enables a researcher to differentiate treatm...

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Analysis of Variance

September 1, 2009
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Analysis of Variance

In an experiment study, various treatments are applied to test subjects and the response data is gathered for analysis. A critical tool for carrying out the analysis is the Analysis of Variance (ANOVA). It enables a researcher to differentiate treatm...

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Simple linear regression

August 5, 2009
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We use the regression analysis when, from the data sample, we want to derive a statistical model that predicts the values of a variable (Y, dependent) from the values of another variable (X, independent). The linear regression, which is the simplest and most frequent relationship between two quantitative variables, can be positive (when X increase, Y increase too) or...

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Simple linear regression

August 5, 2009
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We use the regression analysis when, from the data sample, we want to derive a statistical model that predicts the values of a variable (Y, dependent) from the values of another variable (X, independent). The linear regression, which is the simplest and most frequent relationship between two quantitative variables, can be positive (when X increase, Y increase too) or...

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Kruskal-Wallis one-way analysis of variance

July 31, 2009
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If you have to perform the comparison between multiple groups, but you can not run a ANOVA for multiple comparisons because the groups do not follow a normal distribution, you can use the Kruskal-Wallis test, which can be applied when you can not make ...

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