# Problem 18.7
errorspc_read.table("errorspc.txt",header=T)
p_errorspc[,1]/errorspc[,2]
plot(p)
pbar_mean(p)
abline(h=pbar,lty=3)
lcl_pbar-3*sqrt(pbar*(1-pbar)/200)
ucl_pbar+3*sqrt(pbar*(1-pbar)/200)
c(lcl,ucl)
abline(h=ucl,lty=2)

# Problem 18.8
telespc_read.table("telespc.txt")
p_telespc[,2]/telespc[,1]
plot(p)
pbar_mean(p)
abline(h=pbar,lty=3)
nbar_mean(telespc[,1])
lcl_pbar-3*sqrt(pbar*(1-pbar)/nbar)
ucl_pbar+3*sqrt(pbar*(1-pbar)/nbar)
c(lcl,ucl)
abline(h=lcl,lty=2)
abline(h=ucl,lty=2)
range(p)
plot(p,ylim=c(.07,.16))
abline(h=pbar,lty=3)
abline(h=lcl,lty=2)
abline(h=ucl,lty=2)

# Problem 18.14
teller_scan("teller.txt")
plot(teller)
cbar_mean(teller)
abline(h=cbar,lty=3)
lcl_cbar-3*sqrt(cbar)
ucl_cbar+3*sqrt(cbar)
c(lcl,ucl)
abline(h=ucl,lty=2)
plot(teller,ylim=c(0,13))
abline(h=cbar,lty=3)
abline(h=ucl,lty=2)