Table 4.

Descriptive statistics for variables used in regression models

Variable	1880	1890	1900	1910	1920	1930	1940
Adult Sex Ratioa	318.91	169.35	149.42	130.79	123.20	119.98	113.31
Child-Woman Ratioa	773.36	631.76	603.24	539.87	526.85	458.93	380.02
Mean Temperaturea	10.80	10.15	10.42	10.44	10.16	10.13	10.13
% Sand in Soila	35.32	38.28	38.48	38.96	38.64	38.62	38.62
Depth of Topsoila	9.27	8.84	8.92	8.97	8.68	8.64	8.64
Population Densitya	3.91	6.03	7.32	19.23	20.37	22.76	23.47
% Urbana	2.02	3.25	4.68	8.53	9.92	12.53	15.21
% Scandinavian 1910a	5.33	6.08	5.63	5.77	5.78	5.77	5.77
% German & EE 1910a	11.72	12.35	11.60	11.27	11.19	11.14	11.14
% UK 1910a	3.12	2.98	2.96	2.85	3.02	3.05	3.05
% Mexican 1910a	0.38	0.33	0.35	0.32	0.31	0.31	0.31
% Hispano 1990a	1.30	1.06	1.29	1.30	1.26	1.35	1.35
High Precipitationb	210	292	309	335	344	345	345
Year of Settlementb
1880	107	119	121	124	123	125	125
1890	65	113	117	122	127	129	129
1900	15	20	30	37	40	40	40
1910	24	54	49	72	80	80	80
1920	6	9	13	17	39	41	41
1930	2	7	11	12	14	14	14
1940	1	4	4	4	5	5	5
Not by 1940	8	14	13	13	14	14	14
Total Casesb	228	340	358	401	442	448	448

^aMean value.

^bNumber of cases.