FINAL TERM: EXERCISE NUMBER 1

Creating Basic Histogram

par(mar = c(3, 3, 3, 3))
str(PlantGrowth)  

## 'data.frame':    30 obs. of  2 variables:
##  $ weight: num  4.17 5.58 5.18 6.11 4.5 4.61 5.17 4.53 5.33 5.14 ...
##  $ group : Factor w/ 3 levels "ctrl","trt1",..: 1 1 1 1 1 1 1 1 1 1 ...

#> 'data.frame':    30 obs. of  2 variables:
#>  $ weight: num  4.17 5.58 5.18 6.11 4.5 4.61 5.17 4.53 5.33 5.14 ...
#>  $ group : Factor w/ 3 levels "ctrl","trt1",..: 1 1 1 1 1 1 1 1 1 1 ...
with(PlantGrowth, hist(weight))

Optional Parameters

par(mfrow=c(1,2),mar=c(5,4,4,4)) 
with(PlantGrowth,hist(weight))
with(PlantGrowth,hist(weight,      
      xlim= c(3,7),                       
      ylim= c(0,10),                      
      col= "lightgrey",                   
      border= "black",                         
      main= "Histogram of Plant Weights", 
      xlab= "Dried weight (g)",           
      ylab= "Frequency"))                 

Changing Bin Type

set.seed(1234)
simulated_data <- data.frame(rnorm(n = 1000, mean = 500, sd = 50))
names(simulated_data) <- c("var_name")

str(simulated_data)

## 'data.frame':    1000 obs. of  1 variable:
##  $ var_name: num  440 514 554 383 521 ...

#> 'data.frame':    1000 obs. of  1 variable:
#>  $ var_name: num  440 514 554 383 521 ...

par(mfrow = c(2, 2), mar = c(5, 4, 4, 4))

with(simulated_data, hist(var_name, breaks = "Sturges", main = "Default bins"))
with(simulated_data, hist(var_name, breaks = "Scott", main = "Scott bins"))
with(simulated_data, hist(var_name, breaks = "FD", main = "FD bins"))
with(simulated_data, hist(var_name, breaks = (seq(from = 100, to = 700, 
    by = 10)), main = "Custom bins"))

Advanced Histogram Features

mean.weight <- with(PlantGrowth, mean(weight))
sd.weight <- with(PlantGrowth, sd(weight))
mean.weight

## [1] 5.073

#> [1] 5.07
sd.weight  # see how the mean and sd have now been stored?

## [1] 0.7011918

#> [1] 0.701

par(mar=c(5,4,4,4))
with(PlantGrowth, hist(weight,xlim = c(3,8),ylim = c(0,10), xaxs= "i", yaxs="i"))
abline(v= mean.weight, lty=1, lwd=3,col="blue")
abline(v= mean.weight - (sd.weight), lty=2, lwd=1, col="red")
abline(v= mean.weight + (sd.weight), lty=2, lwd=1, col="red") 
legend("topright",             
       legend=c("Mean", "Mean +/- SD"), 
       col=c("blue","red"),   
       lwd=c(3,1),             
       lty=c(1,2))