15.13 Independent random samples of 6 advertisements were taken from three different magazines: EuroScientist, Focus, and Science Reporter. The fog indices, measuring the reading difficulty of a written text, were taken and are given in the accompanying table. For the one-way analysis of variance model, we write the jth observation from the ith group as Xij = m + Gi + eij where m is the overall mean, Gi is the effect specific to the ith group, and eij is a random error for the jth observation from the ith group.

EuroScientist Focus Science Reporter 12.53 9.46 11.15 11.95 9.26 10.41 10.65 7.88 9.27 9.07 5.99 8.22 8.11 5.32 6.61 5.61 4.82 6.25

a. Estimate m.

b. Estimate Gi for each of the three magazines.

c. Estimate e13, the error term corresponding to the thrid observation (10.65) for EuroScience.