WATER: Sodium Content of Water

In PASWR2: Probability and Statistics with R, Second Edition

Description

An independent agency measures the sodium content in 20 samples from source x and in 10 samples from source y and stores them in the data frame WATER.

Usage

WATER

Format

A data frame with 30 observations on the following 4 variables:

• x (sodium content measured in mg/L)

• y (sodium content measured in mg/L)

• sodium (combined sodium content measured in mg/L)

• source (a factor with levels x and y)

References

Ugarte, M. D., Militino, A. F., and Arnholt, A. T. 2015. Probability and Statistics with R, Second Edition. Chapman & Hall / CRC.

Examples

ggplot(data = WATER, aes(x = sodium, y = ..density.., fill = source)) + 
geom_density(alpha = 0.2)
t.test(sodium ~ source, data = WATER, alternative = "less")

Example output

Loading required package: lattice
Loading required package: ggplot2

	Welch Two Sample t-test

data:  sodium by source
t = -1.8589, df = 22.069, p-value = 0.03822
alternative hypothesis: true difference in means is less than 0
95 percent confidence interval:
       -Inf -0.3665724
sample estimates:
mean in group x mean in group y 
           76.4            81.2 

PASWR2 documentation built on Sept. 5, 2021, 5:44 p.m.