# Data from Myers (1990) Classical and Modern Regression with Applications
 #  10 measurements on spray paint efficiency were taken at each of 4 combinations 
 #  of air velocity and voltage.  The variance of the 10 measurements was estimated 
 #  for each combination, as recorded below 

data <- matrix(scan(),ncol=4,byrow=TRUE)
   50          60      87.5     0.52913
   50          60      88.2     0.52913
   50          60      88.1     0.52913
   50          60      87.3     0.52913
   50          60      89.5     0.52913
   50          60      89.2     0.52913
   50          60      86.2     0.52913
   50          60      85.9     0.52913
   50          60      90.0     0.52913
   50          60      87.0     0.52913
   50         120      82.5     0.39971
   50         120      81.3     0.39971
   50         120      81.6     0.39971
   50         120      80.7     0.39971
   50         120      77.4     0.39971
   50         120      79.3     0.39971
   50         120      81.5     0.39971
   50         120      82.0     0.39971
   50         120      79.7     0.39971
   50         120      79.2     0.39971
   70          60      77.4     0.01841
   70          60      68.1     0.01841
   70          60      70.7     0.01841
   70          60      65.3     0.01841
   70          60      67.0     0.01841
   70          60      61.0     0.01841
   70          60      71.7     0.01841
   70          60      81.7     0.01841
   70          60      79.2     0.01841
   70          60      60.3     0.01841
   70         120      61.2     0.01648
   70         120      50.7     0.01648
   70         120      67.2     0.01648
   70         120      52.3     0.01648
   70         120      55.9     0.01648
   70         120      68.6     0.01648
   70         120      52.0     0.01648
   70         120      69.5     0.01648
   70         120      63.5     0.01648
   70         120      70.1     0.01648

data

WLS1 <- data.frame(data)
colnames(WLS1) <- c("voltage","velocity","y","vweight")
WLS1

rm(data)

WLS1.wlm1 <- lm(y ~ voltage +velocity, weights=vweight, data=WLS1)


 # remove objects when finished

rm(WLS1,WLS1.wlm1)