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 reliability
 of the value of the unknown variable which is predicted
 from a given value of the known variable. The probability
 is that in 68% of the cases the actual value of the
unknown variable will be within the limits of e.

200
. = & BM