Realiza una prueba F para comparar las varianzas de dos muestras de poblaciones normales
x = vector numérico
y = vector numérico
alternative ="two.sided" prueba bilateral (por defecto), "greater" prueba por mayor ó "less" prueba por menor. Puede especificar sólo utilizando la letra inicial
# Datos aleatoriosx =rnorm(50, mean =0, sd =2)y =rnorm(30, mean =1, sd =1)# var.test()var.test(x = x,y = y,alternative ="t") # Prueba bilateral
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## F test to compare two variances
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## data: x and y
## F = 5.5101, num df = 49, denom df = 29, p-value = 5.45e-06
## alternative hypothesis: true ratio of variances is not equal to 1
## 95 percent confidence interval:
## 2.768398 10.366780
## sample estimates:
## ratio of variances
## 5.510093
var.test(x, y, alternative ="g") # Prueba unilateral por derecha
##
## F test to compare two variances
##
## data: x and y
## F = 5.5101, num df = 49, denom df = 29, p-value = 2.725e-06
## alternative hypothesis: true ratio of variances is greater than 1
## 95 percent confidence interval:
## 3.100109 Inf
## sample estimates:
## ratio of variances
## 5.510093
var.test(x, y, alternative ="t") # Prueba unilateral por izquierda
##
## F test to compare two variances
##
## data: x and y
## F = 5.5101, num df = 49, denom df = 29, p-value = 5.45e-06
## alternative hypothesis: true ratio of variances is not equal to 1
## 95 percent confidence interval:
## 2.768398 10.366780
## sample estimates:
## ratio of variances
## 5.510093