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. Author manuscript; available in PMC: 2021 Jan 1.
Published in final edited form as: Environ Int. 2019 Nov 26;134:105287. doi: 10.1016/j.envint.2019.105287

Table 3.

Parameter estimates and standard errors (SEs) from fitting model (1) to the ordinal PS dataset, excluding the litter effect.a

Parameter Estimate Standard Error (SE)
Level 1 background response rate (γ1) 0.0320 0.0370
Level 2 background response rate (γ2) 0.0168 0.0180
Slope (β)b 4.59 1.11
log(BMD05) for level 1 (θ05,1) 5.17 0.217
log(BMD01) for level 2 (θ01,2) 5.23 0.250
a

The model fit adequately according to chi-square goodness-of-fit test: χ52=7.10, p-value = 0.213 (details in Appendix A). In addition, scatterplots of cumulative incidence rates for levels 1 and 2, with the estimated curve over-layed on each (Fig. 2ab), and residual plots of the estimated curves for the two cumulative incidence rates (Fig. 2cd) indicate adequate model fit.

b

The slope was statistically significantly greater than zero (t = 4.15; p-value = 0.009). In addition, an F-test on the equality of the slopes yielded a non-significant result (F1,4 = 2.86; p-value = 0.166).