Monthly Archives: July 2009

Simple visualization of a 11X5 table (for WordPress 2.9 Features Vote Results)

July 31, 2009
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Simple visualization of a 11X5 table (for WordPress 2.9 Features Vote Results)

I guess this is not the number one post I would like to start with on this blog, but I feel the time is right for it (community-wise). I’ll move on to the subject matter in a moment, but first a short intro: This blog is written by Tal Galili. I am an aspiring statistician who

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Simple visualization of a 11X5 table (for WordPress 2.9 Features Vote Results)

July 31, 2009
By
Simple visualization of a 11X5 table (for WordPress 2.9 Features Vote Results)

I guess this is not the number one post I would like to start with on this blog, but I feel the time is right for it (community-wise). I’ll move on to the subject matter in a moment, but first a short intro: This blog is written by Tal Galili. I am ...

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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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Kruskal-Wallis one-way analysis of variance

July 31, 2009
By

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 ...

Read more »

Analysis of variance: ANOVA, for multiple comparisons

July 30, 2009
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Analysis of variance: ANOVA, for multiple comparisonsThe ANOVA model can be used to compare the mean of several groups with each other, using a parametric method (assuming that the groups follow a Gaussian distribution).Proceed with the following example:The manager of a supermarket chain wants to see if the consumption in kilowatts of 4 stores between them are equal. He...

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Analysis of variance: ANOVA, for multiple comparisons

July 30, 2009
By

Analysis of variance: ANOVA, for multiple comparisonsThe ANOVA model can be used to compare the mean of several groups with each other, using a parametric method (assuming that the groups follow a Gaussian distribution).Proceed with the following example:The manager of a supermarket chain wants to see if the consumption in kilowatts of 4 stores between them are equal. He...

Read more »

Comparison of two proportions: parametric (Z-test) and non-parametric (chi-squared) methods

July 29, 2009
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Consider for example the following problem.The owner of a betting company wants to verify whether a customer is cheating or not. To do this want to compare the number of successes of one player with the number of successes of one of his employees, of w...

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Comparison of two proportions: parametric (Z-test) and non-parametric (chi-squared) methods

July 29, 2009
By

Consider for example the following problem.The owner of a betting company wants to verify whether a customer is cheating or not. To do this want to compare the number of successes of one player with the number of successes of one of his employees, of w...

Read more »

Wilcoxon signed rank test

July 29, 2009
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Non-parametric statistical hypothesis test, for the comparison of the means between 2 paired samplesThe mayor of a city wants to see if pollution levels are reduced by closing the streets to the car traffic. This is measured by the rate of pollution every 60 minutes (8am 22pm: total of 15 measurements) in a day when traffic is open, and...

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Wilcoxon signed rank test

July 29, 2009
By

Non-parametric statistical hypothesis test, for the comparison of the means between 2 paired samplesThe mayor of a city wants to see if pollution levels are reduced by closing the streets to the car traffic. This is measured by the rate of pollution every 60 minutes (8am 22pm: total of 15 measurements) in a day when traffic is open, and...

Read more »