It is common that lecturers obtain reputations for being ‘hard’ or ‘light’ markers, but there is often little to substantiate these reputations. A group of students investigated the consistency of marking by submitting the same essays to four different lecturers. The outcome was the percentage mark given by each lecturer and the predictor was the lecturer who marked the report (tutor_marks.sav). Compute the F-statistic for the effect of marker by hand.