InsectSprays

Effectiveness Of Insect Sprays

A pre-loaded example dataset in R

Main page: https://www.rdocumentation.org/packages/datasets/versions/3.6.2/topics/InsectSprays

head(InsectSprays)

##   count spray
## 1    10     A
## 2     7     A
## 3    20     A
## 4    14     A
## 5    14     A
## 6    12     A

require(stats); require(graphics)
boxplot(count ~ spray, data = InsectSprays,
        xlab = "Type of spray", ylab = "Insect count",
        main = "InsectSprays data", varwidth = TRUE, col = "lightgray")

fm1 <- aov(count ~ spray, data = InsectSprays)
summary(fm1)

##             Df Sum Sq Mean Sq F value Pr(>F)    
## spray        5   2669   533.8    34.7 <2e-16 ***
## Residuals   66   1015    15.4                   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

opar <- par(mfrow = c(2, 2), oma = c(0, 0, 1.1, 0))
plot(fm1)

fm2 <- aov(sqrt(count) ~ spray, data = InsectSprays)
summary(fm2)

##             Df Sum Sq Mean Sq F value Pr(>F)    
## spray        5  88.44  17.688    44.8 <2e-16 ***
## Residuals   66  26.06   0.395                   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

plot(fm2)

par(opar)