Esercizio_2b

#     ESERCIZIO 2b
rm(list=ls())
library(moments)
library(car)

data2 <- read.table("Exercise2b.txt", header = T, sep = "\t")
duration <- c(5, 10, 20, 30, 40, 50, 60, 120, 180)
for (i in 2:length(duration)+1) {
  colnames(data2)[i] <- i
}

par <- matrix(NA, nrow = length(duration), ncol = 3)
colnames(par) <- c("media", "varianza", "skewness")

df <- data2[ ,2:10]

media <- rep(0, length(duration))
varianza <- rep(0,length(duration))
skewness <- rep(0,length(duration))
for (i in 1:length(duration)) {
  x <- df[ ,i]
  media[i] <- mean(x)
  varianza[i] <- var(x)
  skewness[i] <- skewness(x)
  par[i,1] <- media[i]
  par[i,2] <- varianza[i]
  par[i,3] <- skewness[i]
}

plot(duration, par[ ,1], ylab = "value", main = "Media", type = 'l', col = 'red', lwd = 2)
plot(duration, par[ ,2], ylab = "value", main = "Varianza", col = 'blue', lwd = 2, type = 'l')
plot(duration, par[ ,3], ylab = "value", main = "coeff. di Skewness", col = 'green', lwd = 2, type = 'l')