Chapter01 {DanielBiostatistics10th}

Chapter 1: Introduction to Biostatistics

Description

Functions and examples for Chapter 1, Introduction to Biostatistics.

Usage

sampleRow(x, size, replace = FALSE, prob = NULL)

Arguments

x

a data.frame

size

positive integer scalar, number of rows to be selected

replace

logical scalar, whether sampling should be with replacement (default FALSE)

prob

numeric vector of probability weights for each row of input x being sampled. Default NULL indicates simple random sampling

Value

Function sampleRow returns a data.frame, a simple random sample from the input.

See Also

sample.int

Examples

library(DanielBiostatistics10th)
# To run a line of code, use shortcut
# Command + Enter: Mac and RStudio Cloud
# Control + Enter: Windows, Mac and RStudio Cloud
# To clear the console
# Control + L: Windows, Mac and RStudio Cloud

# Example 1.4.1; Page 8 (10th ed), Page 7 (11th ed)
class(EXA_C01_S04_01) # `EXA_C01_S04_01` is a 'data.frame' (a specific class defined in R)
dim(EXA_C01_S04_01) # dimension, number-row and number-column
head(EXA_C01_S04_01, n = 8L) # first `n` rows of a 'data.frame'
names(EXA_C01_S04_01) # column names of a 'data.frame'
EXA_C01_S04_01$AGE # use `$` to obtain one column from a 'data.frame' 
sampleRow(EXA_C01_S04_01, size = 10L, replace = FALSE) # to answer Example 1.4.1

# Example 1.4.2; Page 11 (10th ed), Page 10 (11th ed)
EXA_C01_S04_01[seq.int(from = 4L, to = 166L, by = 18L), ]