p_value<-function(cdf,x,parament=numeric(0),side=0)

{

n<-length(parament)

p<-switch(n+1,

cdf(x),

cdf(x,parament),

cdf(x,parament[1],parament[2]),

cdf(x,parament[1],parament[2],parament[3])

)

if(side<0) p

else if (side>0) 1-p

else

    if(p<0.5) 2*p

    else 2*(1-p)

}

mean.test1<-function(x,mu=0,sigma=-1,side=0)

{

n<-length(x)

xb<-mean(x)

if(sigma>0)

{

z<-(xb-mu)/(sigma/sqrt(n))

p<-p_value(pnorm,z,side=side)

data.frame(mean=xb,df=n,Z=z,p_value=p)

}

else

{

t<-(xb-mu)/(sd(x)/sqrt(n))

p<-p_value(pt,t,parament=n-1,side=side)

data.frame(mean=xb,df=n-1,T=t,p_value=p)

}

}