TABLE XIV

	Av. % of difference in favor of		Av. % of difference in favor of		Av. % of difference in favor of
	Cases	First	Cases	Last	Cases	No tendency
Angier			7	19.1	4	4.9
Baldwin	4	20.5			1	3.4
Bell			1	18.2	4	6.3
Davison			2	31.2
Dunlap	1	11.4			1	2.2
Holt			10	19	2	6
Hylan	2	16	5	25.4	5	4.9
Johnston	2	25.2	4	35.5	4	4.2
Meakin			2	39.7
Meriam	1	29.6			1	2.2
Miller			3	17.1	4	5.5
Moore			1	11.4	1	2.2
Olmsted	1	15.2
Peterson			1	17	1	9
Rogers			1	10.2	1	5.6
Rouse					1	1.2
Shaw	6	16.7			5	7
Windate			1	11.4	1	1.2
Yerkes			2	42.7

a. Relation of the Error to the Absolute Length of the Total Exposure. Table XV is set to answer this question. It is unsatisfactory in that but two observers took part in both XIII and XV. The material used for judgment consisted of the same cards used in the earlier experiment, but presented now in the One-Group Apparatus. The time of exposure was changed from 3/5 sec. to 1/25 sec. for each group. As the space-error was eliminated, the tendency to a time-error, if present at all, would presumably have freer play.

But the difference-values of the new table are for the most part very small. We have thus the further fact about the time-error that, under the conditions studied, it appears to be independent of the absolute length of exposure, when the groups are equal in this respect. To this we may add another fact drawn from Table XIV, that with the One-Group Apparatus the time-error is greater on the whole where the groups are differentiated by other factors. Thirdly, the values for Table XIII show that with all complicating factors withdrawn, except the differences in position, the error is at a maximum. This may be significant of the effect of space-differences upon that error, or, more probably, be due to the general difference between work by daylight and work in a dark room by artificial light. We shall be better able to consider this later.