Table I.

Summary Statistics: Aggregate Data by County Groups, c. 1910.

	Whole Sample	By Hookworm Infection		Source
		> 40%	<40%
Hookworm-Infection Rate	0.328 (0.234)	0.560 (0.136)	0.161 (0.117)	RSC Annual Reports
Treatments Issued by the RSC, Per Capita	0.059 (0.067)	0.096 (0.068)	0.031 (0.052)	RSC Annual Reports
Individuals Treated at Least Once by the RSC, Per Capita1	0.029 (0.029)	0.048 (0.027)	0.015 (0.022)	RSC Annual Reports
School Enrollment, 1910	0.721 (0.104)	0.711 (0.099)	0.729 (0.108)	IPUMS, author's calculations
Δ Schooling Enrollment, 1910-20	0.089 (0.080)	0.103 (0.090)	0.078 (0.072)	IPUMS, author's calculations
Generalized 5-year Fertility Rate	0.558 (0.130)	0.599 (0.127)	0.529 (0.125)	IPUMS, author's calculations
Δ Generalized Fertility Rate, 1910-1920	−0.060 (0.091)	−0.080 (0.102)	−0.046 (0.080)	IPUMS, author's calculations
Age-adjusted 5-year Fertility Rate	0.545 (0.139)	0.585 (0.134)	0.517 (0.136)	IPUMS, author's calculations
Δ Age-adjusted Fertility Rate, 1910-1920	−0.054 (0.089)	−0.076 (0.097)	−0.038 (0.080)	IPUMS, author's calculations
Sample Size	115	48	67

Notes: Displayed are means and (in brackets) standard deviations, averaged at the level of State Economic Area (county group). The underlying sample of children includes native born blacks and whites age 8-16 in IPUMS from RSC surveyed units in the indicated years. The adult sample includes native born black and white females aged 15-49 in IPUMS from RSC surveyed units in the indicated years. School enrollment is calculated using all native born black and whites in the RSC surveyed units between the ages 8 and 16. The Generalized Fertility Rate is the average number of children less than 5 years per female aged 15-49. The age-adjusted fertility is adjusted for the age composition of the population using a regression of fertility on age dummies in the 1910

¹The treatment intensity variables are only available for 114 (rather than 115) SEAs.