clase 3

set.seed(2021)
Na_1<-rnorm(20,45,4)
Na_2<-rnorm(20,38,4.2)
df_Na<-data.frame(Na_1,Na_2) #Data frame forma 1
Na<-c(Na_1,Na_2)
metodo<-gl(2,20,40,c("moderno","usual"))
df<-data.frame(Na,metodo) # Data frame forma 2
library(lattice)

bwplot(df$Na~df$metodo)

medias=tapply(df$Na,df$metodo,mean)

desv=tapply(df$Na,df$metodo,sd);desv

##  moderno    usual 
## 4.355080 4.180158

cv=100*tapply(df$Na,df$metodo,sd)/ tapply(df$Na,df$metodo, mean);cv

##   moderno     usual 
##  9.350384 11.758616

abs(medias[1]-medias[2])

##  moderno 
## 11.02675

100*(medias[1]-medias[2])/medias[2]

## moderno 
## 31.0178

plot(density(Na_1),col="blue", lty=2)

lines(density(Na_2),col="red")
legend(52,0.08,c("Moderno", "Usual"),col=c("blue","red"),pch=16)

pr_1=t.test(x= Na_1,y=Na_2, alternative = "t", mu = 0, var.equal = T,conf.level = 0.95)
pr_1

## 
##  Two Sample t-test
## 
## data:  Na_1 and Na_2
## t = 8.169, df = 38, p-value = 6.845e-10
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##   8.294173 13.759321
## sample estimates:
## mean of x mean of y 
##  46.57649  35.54974