Table 1. Investigation 1. Chi -values According to Bartlett’s Test. (Series 4—15). 
Operator 
no. 
11.2.63 
12.2.63 
13.2.63 
18.2.63 
i 
37. 1 
highly sign 
80. 1 
highly sign 
18.5 
not sign 
14.4 
not sign 
2 
7.3 
not sign 
21.3 
almost sign 
50.2 
highly sign 
10. 8 
not sign 
3 
65.1 
highly sign 
24.4 
almost sign 
103 
highly sign 
1.3 
not sign 
4 
27 
sign 
39 
highly sign 
9.8 
not sign 
19. 15 
not sign 
Treatment of Data 
Averages and standard deviations are computed from every series. 
Grand averages and root mean square values of standard deviations 
are computed for each operator everyday. 
Primary data in these experiments are easily grouped for variance 
analysis in order to investigate differences in the averages due to alco 
hol. However, this analysis can be applied when the observations are 
independent and normally distributed with the same variance (see [1] 
16.2). Bartlett’s test has been used to determine if the computed stand 
ard deviations are all estimates of the same theoretical value (see [1] 
11.6). The test is applied to the coordinate of the horizontal parallax 
only because we are most interested in the influences upon stereo 
vision. According to the principles of the test the differences between 
the standard deviations are said to be 
not significant 
if 
chi 2 
< 
Chi 2 o.95 
almost significant 
if chi 2 0.95 
^ chi 2 
< 
chi 2 o.99 
significant 
if chi 2 o 99 
^ chi 2 
< 
chi 2 0.999 
highly significant 
if chi 2 0 999 
^ chi 2 
Table 2. Investigation 2. Chi 2 -values According to Bartlett’s Test. (All Series.) 
Operator 
no. 
4.3.63 
6.3.63 
1 
8.895 
12.634' 
2 
7.358 
0.834 
3 
14.838 
6.763 
4 
9.087 
11.085 
4 
12.158 
17.175 
No values is significant. 
475