Egon S. Pearson 
77 
i.e. of over twice Ss, the standard deviation of first differences. In the diagram of 
Figure 16, ten observations are represented ; the break between yt,-i fi-nd ijt or 
yt'»yt-i, is supposed to be equal to, or greater than, '07. If this large break 
influences the succeeding judgments, it is to be expected that the differences 
yt+i'^yt> yt+-2'^yt, ■■• etc. will be smaller on the average than the differences 
yt'^'yt-u yf^yt-^, ■■■ etc. 
The horizontal line intersecting each graph gives the mean of the first 50 observations in that series. 
Fig. 15. 10 Second Counting. Diagrams representing variations in judgment. 
