Egon S. Pearson 
57 
58 
56 
•54 
52 
•50 
48 
■46 
■44 
■42 
■40 
•38 
■36 
34 
■32 
30 
■28 
226 
P, = --741 \ 
5 =--00:307 \ 
. a\= -078 \ 
The horizontal line intersecting each graph gives the mean of the first 50 observations in that series. 
Fig. 6. Trisection. Diagrams representing variations in judgment (continued). 
XV has a large linear sessional change, but superimposed on this there must be 
considerable correlated variations, for the removal of the best fitting straight line 
only reduces (-8568) to /a/ (-6810). XVIII has variations altogether on a smaller 
scale ; the correlation of successive judgments is low and it is barely affected by the 
removal of the linear sessional change. And yet though the o-j for XV is more 
than twice as great as for XVIII, the cr/s, or measures of the average jump in 
estimation from judgment to judgment, are practically identical; the importance 
of this constant cr^ as a measure of variability of judgment is discussed on p. 09 
below. 
