EMPLOYMENT PSYCHOLOGY 
See Kelley (86, p. 173) and Ruml (158). The second term 
in formula 40 is called the coefficient of alienation (k) by 
Kelley. The relationship between 7 and € is the same as 
that of the sine of an angle and the cosine. It is brought 
out in Figure 27. Compare, for example, the standard error 
of estimate of a correlation of .30 with one of .10. Note that 
it is nearly as large. Then compare the standard error of 
estimate of a correlation of .75 with one of .95. Note that 
the latter is only about half as large as the former. 
10 = == — - 
80 +4 
5 | 
460 
3 
3 Pi tr 
3 
2 
Oo 
20 4 
.00 Loo ea = — 
.00 20 40 60 .80 1.2) 
Coefficient of Correlation 
Figure 27: Relationship between the coefficient of correlation (r) and the 
coefficient of alienation or standard error of estimate (€). 
The standard error of estimate gives an idea of the relia- 
bility of the value of the unknown variable which is pre- 
dicted from a given value of the known variable. The prob- 
ability is that in 68% of the cases the actual value of the 
unknown variable will be within the limits of e. 
200 
. = & BM