function(x, alfa)
{
	n <- length(x)
	cf <- qt(1 - alfa/2, n - 1)
	upper <- mean(x) + (cf * std(x))/
		sqrt(n)
	lower <- mean(x) - (cf * std(x))/
		sqrt(n)
	conint.norm <- c(lower, upper)
	conint.norm
}
