Analysis of Fertilizers

Here again we create a series of dummy variables (each variable being coded either 1 for "present" or 0 for "absent") from the single original YOR "Fertilizers" field. An examination of these simple correlations with crop yield indicates that only two types of fertilizer show a significant and positive correlation with crop yield, and, interestingly, these both have something to do with the General Hydroponics brand.

Cypher 5 - Fertilizer	Correlation	Significance
C=Hydroponic formulation, Dyna-Gro Liquid	.032	.695
D=Hydroponic formulation, Other	-.007	.935
F=Hydroponic formulation, Eco Brand, Liquid	.004	.956
G=Hydroponic formulation, General Hydroponics Flora Series Liquid	.249**	.002
H=Hydroponic formulation, General Hydroponics Brand, Other	.215**	.008
I=Hydroponic formulation, Other, Dry	-.178*	.028
J=Hydroponic formulation, Other, Dry 2 part	.089	.272
K=Hydroponic formulation, Other, Liquid 2 part	.020	.803
O=Hydroponic formulation, Mix of more than one brand	-.085	.296
Q=Soil formulation, Peters Brand	-.096	.239
R=Soil formulation, Miracle Grow Brand	-.095	.242
T=Soil formulation, Other, Dry	-.135	.096
U=Soil formulation, Other, Liquid	-.046	.574
V=Soil formulation, Other, Home Made	-.093	.255
W=Soil formulation, Organic, Dry	-.074	.361
X=Soil formulation, Organic, Liquid	-.041	.616
Z=Pyraponic	-.118	.146
_-Not Available	-.180*	.026
** Correlation is significant at the 0.01 level * Correlation is significant at the 0.05 level Number of records=153

However, once again we must not jump to conclusions. Only subsequent regression modeling will tell us if these apparent relationships are real, or if some other, hidden influence is operating here.