• Use File > Change dir...
• setwd("P:/Data/MATH/Hartlaub/Nonparametrics")
• getwd()

Reading data (Creating a dataframe)

• mydata=read.csv(file=file.choose())

• mydata #shows the entire data set
• head(mydata) #shows the first 6 rows
• tail(mydata) #shows the last 6 rows
• str(mydata) #shows the variable names and types
• names(mydata) #shows the variable names
• ls() #shows a list of objects that are available
• attach(mydata) #attaches the dataframe to the R search path, which makes it easy to access variable names

• mean(x) #computes the mean of the variable x
• median(x) #computes the median of the variable x
• sd(x) #computes the standard deviation of the variable x
• IQR(x) #computer the IQR of the variable x
• summary(x) #computes the 5-number summary and the mean of the variable x
• cor(x,y) #computes the correlation coefficient

Graphical Displays

• hist(x) #creates a histogram for the variable x
• boxplot(x) # creates a boxplot for the variable x
• boxplot(y~x) # creates side-by-side boxplots
• stem(x) #creates a stem plot for the variable x
• plot(y~x) #creates a scatterplot of y versus x
• abline(lm(y~x)) #adds regression line to plot
• lines(lowess(x,y)) # adds lowess line (x,y) to plot

Nonparametric Tests

• binom.test(x, n, p) #Binomial test for proportions
• SIGN.test(x, md=0) #Need BSDA package, Sign test
• wilcox.test(x) #Wilcoxon signed rank test
• wilcox.test(x, y) #Wilcoxon rank sum test
• ansari.test(x, y) #Ansari-Bradley test
• fligner.test(x, g) #Fligner-Killeen test of equal variances; g is a grouping variable
• ks.test(x,y) #Kolmogorov-Smirnov test
• kruskal.test(x, g) #Kruskal-Wallis rank sum test; g is a grouping variable
• kruskalmc(response, group) #Need pgirmess package; g is a grouping variable
• JT.test(data, g) #Need SAGx package; Jonckheere-Terpstra test; data is a matrix; g is a grouping variable
• cor.test(x,y) #correlation test plus CI for several measures of association (r, rho, tau)
• friedman.test(y~A|B) # y are the data values, A is a grouping factor, and B is a blocking factor