Table 2.

Measures of allelic association ψ in random haplotypes

Definition	Symbol	Estimate ψ̂ = D̂/C
Covariance	D	D̂= |π11π22 − π12π21|
Association	ρ	D̂/Q(1 − R)
Correlation	r	D̂/
Regression	b	D̂/R(1 − R)
Frequency difference	f	D̂/Q(1 − Q)
Delta	δ	D̂/Q(1 − R − Q + RQ + D)
Yule	y	D̂/[2Q(1 − Q)R(1 − R) + D(1 − 2Q)(1 − 2R) + 2D2]

D̂ is an estimate with expected value D and information K_D. 

K_D = n/[Q(1 − Q)R(1 − R) + D(1 − 2Q)(1 − 2R) − D²] (ref. 34, equation 3.8).