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A tutorial of performing statistical analysis with the Kruskal-Wallis test.

A tutorial of performing statistical analysis with the Wilcoxon signed-rank test.

A tutorial on statistical inference about difference between two population proportions.

A tutorial on statistical inference about population mean between two matched samples.

Quantitative data, also known as continuous data, consists of numeric data that support arithmetic operations. This is in contrast with qualitative data, whose values belong to pre-defined classes with no arithmetic operation allowed. We will explain how to apply some of the R tools for quantitative data analysis with examples.

A tutorial on the concept of data frames in R. Using a build-in data set sample as example, discuss the topics of data frame columns and rows. Explain how to retrieve a data frame cell value with the square bracket operator. Plus a tips on how to take preview of a data frame.