The confidence limits were determined from statistical tables for 10 degrees of freedom and for the 
confidence levels of 5 and 1 per cent. In practice the former figure seems to be more usual. 
Under these conditions the following confidence intervals are found. 
For confidence level 5 per cent: 0.7 $,— 1.8 Sy 
> " "0pm "968—238 
If the y-parallaxes were measured in 9 points only, the degrees of freedom are reduced to 4. For the 
same confidence levels as above the following confidence intervals are found: 
5 per cent: 0.6 $,—2.9 s, 
1 per cent: 0.584—4.4 © 
3.4 The accuracy to be expected from the controlled tests 
According to the discussions above, the predictions below can be performed concerning the mean 
square values of the discrepancies in planimetry and elevation check points to be expected from the 
controlled tests of Sub-commissions IV:1 to IV:3. The conditions which clearly have been stated 
must of course be taken into account. 
In particular, since the models were not adjusted up to the requirements of the method of least 
squares, the standard error of unit weight of the y-parallax measurements is not representative of 
the actual adjustment situation of the models. With a certain approximation, the mean square value 
of the measured y-parallaxes is therefore used as a substitute for the standard error of unit weight. 
The confidence intervals will be kept unchanged since the operator doubtless had the opportunity 
to correct the y-parallaxes almost completely in at least five orientation points. 
Under these assumptions the following results are derived. 
Sub-commission IV:1 
Camera R.C. 5a 11.5/18. Film. S$m15—=8.3 microns (average). S=8000. 
M,=0.100 m 0.070— 0.180 m (5 per cent) 
0.060— 0.220 m (l1 per cent) 
M,—0.100 m 0.070—0.180 m (5 per cent) 
0.060—0.220 m (1 per cent) 
M,—0.133 m 0.093— 0.240 m (5 per cent) 
0.080— 0.292 m (1 per cent) 
Camera R.C. 7a 10/15. Plates. sm;;=8.9 microns (average) S= 9000. 
M4—0.120 m 0.084— 0.216 m (5 per cent) 
0.072— 0.264 m (1 per cent) 
M,—0.120 m 0.084— 0.216 m 
0.072— 0.264 m 
M,=0.160 m 0.120— 0.289 m 
0.096 —0.350 m 
Sub-commission IV :2 
Camera R.C. 5 21/18. Film. $3,5— 7.1 microns (average) S— 5000 
M4—0.039 m 0.027—0.070 m (5 per cent) 
0.023—0.086 m (1 per cent) 
24 
  
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