82 
On the Variations in Personal Equation 
IX. Experiment D. Estimation of 10 seconds. 
Reduction of Observations. 
((() Tlie Individual Series. 
In Table XV arc given the values of d (the mean of the 63 observations of a 
series, not those of Group 1 only), and of o-j and for the individual series; the 
low values of will be noted at once, and also the high values of o-j compared with 
those in the Counting Experiment. In Figure 19 below the means have been 
plotted to order of series, and if 
X is the mean in the factor ejp, 
y the order of series, 
z the time in hours and fractions of an hour between 10 a.m. on December 7th, 
and the commencement of series, 
TABLE XV. 
Constants of Individual Series {Estimate of Seconds). 
Series 
d 
Pi 
Time of Start 
Date (1920) 
I 
1 
151 
•1217 
•1518 + 
■0932 
10.45 a.m. 
II 
1 
•111 
•1254 
+ 
•2332 + 
■0902 
11.30 a.m. 
III 
1 
■109 
•1330 
•0249 + 
■0953 
12.10 p.m. 
- 7th December 
IV 
1 
•052 
•1393 
+ 
•1803 + 
■0923 
2.0 p.m. 
V 
■973 
•1292 
+ 
•2632 + 
■0888 
3.0 p.m. 
J 
VI 
1 
•119 
•1349 
+ 
•1300 + 
■0938 
10.15 a.m. 
VII 
1 
•Oil 
•1312 
+ 
■3673 + 
■0825 
11.0 a.m. 
VIII 
1 
•073 
•1318 
+ 
•1631 + 
■0929 
2.0 p.m. 
■ 8tli December 
IX 
1 
•003 
•1108 
+ 
•1976 + 
■0917 
2.30 p.m. 
X 
1 
•089 
•0989 
+ 
•0380 + 
■0953 
3.15 jj.m. 
XI 
1 
•204 
•1519 
+ 
•3405 + 
■0843 
10.0 a.m. 
■ 
XII 
1 
204 
•1467 
+ 
■1415 + 
•0935 
11.0 a.m 
XIII 
1 
091 
•1166 
+ 
•3241 + 
■0854 
12.0 midday 
■ 9th December 
XIV 
1 
•036 
•1059 
+ 
•0566 ± 
■0951 
2.0 p.m. 
XV 
1 
•132 
■1884 
+ 
•4814 + 
■0733 
3. 15 p.m. 
XVI 
1 
170 
•1500 
+ 
■1036 + 
■0944 
10.0 a.m. 
^ 
XVII 
1 
421 
•1520 
■0834 + 
■0947 
11.0 a.m. 
XVIII 
1 
300 
•1591 
+ 
■2314 + 
■0903 
12.0 midday 
- 10th December 
XIX 
1 
243 
•1708 
+ 
■2260 + 
■0905 
2.0 p.m. 
XX 
1 
170 
•1833 
+ 
1659 + 
■0928 
2.45 p.m. 
Correlation between pi and , r^^ = +'176 + ^146 (calculated from correlation of ranks). 
we have for the regression lines 
X - 1-1333 = + -01018 (y/ - 10'5) (xxxix), 
X - 1 1333 = + -002493 (z - 38-62) (xl). 
The coefficients of correlation are 
Txz = + -638 ± -089, r^y = + -562 + -103, r,, = + -983 ± -005, 
