library(scales)
alpha(colours(), 0.5)
windows(6,4)
par(oma=c(0,0,0,0),mar=c(2,1,0,0))
mean=0; sd=1
lb=1.64; ub=4
x <- seq(-4,4,length=100)*sd + mean
hx <- dnorm(x,mean,sd)

plot(x, hx, type="n", xlim=c(-4, 8), ylim=c(0, 0.5), ylab = "", xlab = "", axes=FALSE)
axis(1, lwd=2,cex.axis=1.3,line=-0.5)

shift = qnorm(1-0.05, mean=0, sd=1)*1.7
xfit2 <- x + shift
yfit2 <- dnorm(xfit2, mean=shift, sd=1)

# Print null hypothesis area
col_null = "#FF0000E3"
lines(x, hx, lwd=2)
i <- x >= lb & x <= ub
polygon(c(lb,x[i],ub), c(0,hx[i],0), col="#FF0000E3",lwd=3,ylim=c(0,0.48)) 
area <- pnorm(ub, mean, sd) - pnorm(lb, mean, sd)

# The alternative hypothesis area

## The red - underpowered area
lb <- min(xfit2)
ub <- round(qnorm(.95),2)
col1 = "#3D3D3D80"

i <- xfit2 >= lb & xfit2 <= ub
polygon(c(lb,xfit2[i],ub), c(0,yfit2[i],0), col=col1)


## The green area where the power is
col2 = "#76EE0080"
lines(c(ub,xfit2,max(xfit2)), c(0,yfit2,0),lwd=2)

# Outline the alternative hypothesis
lines(xfit2, yfit2, lwd=2)
legend("topright", inset=.05, c(expression(paste("Type I error (",alpha,")")),expression(paste("Type II error (",beta,")"))), fill=c(col_null, col1, col2), horiz=FALSE)
lines(c(1.64,1.64),c(0,0.45),col="blue")

mtext(side=1,expression(paste("1-",alpha)),cex=1.5,line=-4.5,adj=0.33)
mtext(side=1,expression(paste("1-",beta)),cex=1.5,line=-4.5,adj=0.62)

arrows(2.9, 0.03, 2.1, 0.01, lwd=2)
mtext(side=1,expression(paste(alpha)),cex=1.5,line=-2.4,adj=0.59)
mtext(side=1,expression(paste(beta)),cex=1.5,line=-2,adj=0.43)
mtext(side=3,expression("H"[0]),line=-3.5,adj=0.34,cex=1.5)
mtext(side=3,expression("H"[a]),line=-3.5,adj=0.61,cex=1.5)