APPENDIX TABLE 2.

OLS REGRESSIONS: CORRELATES OF MALARIA INCIDENCE AND ENVIRONMENTAL FACTORS (dependent variable: In(fort malaria incidence rate))

	(1)			(2)			(3)
	Using All Forts			Using Forts in 1829–1838			Using Forts in 1871–1874
Variables	Mean	Estimate	t-value	Mean	Estimate	t-value	Mean	Estimate	t-value
Dependent variable	−2.1462			−2.0176			−2.2268
Annual mean temperature (°F)	53.59	0.5021	8.63	53.68	0.6819	6.13	53.54	0.4064	5.94
Temperature2 / 100	29.74	−0.3886	−7.48	29.75	−0.4917	−4.71	29.74	−0.3159	−5.19
Accumulated rainfall (inches)	20.25	0.0045	0.76	28.25	−0.0443	−3.02	15.25	0.0028	0.34
S.D. of elevation (σ) (feet)	110.93	−0.0012	−2.58	31.6	−0.0109	−1.87	160.64	−0.0006	−1.1
County land improvement ratio
Ratio if σ < 30	0.1745	0.5446	2.28	0.2117	−1.3364	−3.13	0.1511	1.2228	3.98
Ratio if σ ≥ 30	0.1972	−0.3466	−1.7	0.1441	−1.425	−2.22	0.2305	0.2421	1.04
Dummy = 1 if adjacent to ocean	0.2574	−0.7961	−5.34	0.3545	−0.5388	−2.65	0.1966	−0.9264	−4.31
Constant term		−17.27	−11.13		−21.72	−7.21		−14.6	−8.02
F (p-value)		39.81 (0.000)			35.22 (0.000)			18.47 (0.000)
Adjusted R2		0.3228			0.5224			0.2589
n		571			220			351

Note: Rainfall is accumulated only for the months whose monthly mean temperatures are over 59 °F.