R code for cola example

To find x*:

xstar <- qnorm(.05,355,2/sqrt(12))

zstar <- qnorm(.05)
xstar <- 355 + zstar*2/sqrt(12)  # understand?

Now, make a decision based upon this sample of volumes, measured on a particular day:

354.3 352.9 357.9 351.6 353.4 354.5 355.3 358.9 356.8 354.9 351.4 354.6

volumes <- scan()

# then select and copy the 12 numbers from the web page, 
# copy them at the prompt,
# double [enter key] to end.

# Or just type in the numbers.