Using statistical functions

R is highly productive in doing statistical computing and modeling since it provides a good variety of functions ranging from random sampling to statistical testing. The functions in the same category share a common interface. In this section, I will demonstrate a number of examples so that you can draw inferences about the usage of other similar functions.

Sampling from a vector

In statistics, the study of a population often begins with a random sample of it. The sample() function is designed for drawing a random sample from a given vector or list. In default, sample() draws a sample without replacement. For example, the following code draws a sample of five from a numeric vector without replacement:

sample(1:6, size = 5)
## [1] 2 6 3 1 4 

With replace = TRUE, the sampling is done with replacement:

sample(1:6, size = 5, replace = TRUE)
## [1] 3 5 3 4 2 

Although sample() is often used to draw samples from a numeric vector, it also works with other...