Table 1.

Results for statistical tests of experimental hypotheses^a,b

	df	T	P
Hypothesis 1c
Cresco high	34	2.89	0.003
Cresco low	34	4.09	<0.001
Hopkinton high	33	3.12	0.002
Hopkinton low	33	1.75	0.044
Susceptible	33	0.53	0.301
Hypothesis 2d
Cresco high/low
F2	70	3.34	0.001
F4	34	2.53	0.016
F6	34	1.38	0.177
Hopkinton high/low
F2	68	0.06	0.950
F4	34	0.59	0.561
F6	34	1.51	0.139
Hypothesis 3e
Cresco high	34	9.14	<0.001
Cresco low	34	7.57	<0.001
Hopkinton high	34	5.60	<0.001
Hopkinton low	34	7.22	<0.001

^aAnalyses presented in this table were conducted on correct survival in plant-based bioassays. Correct survival was calculated by dividing survival on Bt corn by survival on non-Bt corn. Additional details are provided in the Data Analysis section of the Materials and Methods.

^bMeans tested in Table 1 correspond to the means presented in Fig. 2.

^cHypothesis 1: One-tailed T-tests of corrected survival between F₁ and F₆ for western corn rootworm strains. H₀: corrected survival is equal at beginning of the experiment compared to the end of the experiment. H_A: corrected survival is significantly lower at the end of the experiment compared to the beginning of the experiment.

^dHypothesis 2: Two-tailed T-tests between high-density and low-density treatments within the same parental background (i.e., Hopkinton or Cresco) at each of three generations (i.e., F₂, F₄ and F₆). H₀: corrected survival is equal between strains reared at high density vs low density. H_A: corrected survival is significantly different between strains reared at high density vs low density.

^eHypothesis 3: One-tailed T-tests comparing corrected survival at F₆ for each strain to corrected survival for Susceptible at F₆. H₀: corrected survival is equal between each strain and the Susceptible strain at the end of the experiment. H_A: corrected survival is significantly lower in the Susceptible strain compared to each strain at the end of the experiment.