= Solution
Compare the species-only model against the additive day-and-species model. The <null hypothesis> is $H_0:d_2=d_3=0$, with the alternative that at least one is nonzero. The likelihood-ratio statistic is the reduction in <residual deviance>,
$$
\boxed{G^2=14.987-14.646=0.341.}
$$
Under the <null hypothesis>, regular <binomial likelihood> asymptotics give $G^2\overset{\rm approx}{\sim}\chi^2_2$, because the larger model has two additional parameters. For this <chi-squared distribution> the upper-tail probability is $\exp(-0.341/2)\simeq0.843$. \b[There is no evidence of a day effect after controlling for species], and the species-only model is a reasonable simpler choice. The sequential day-only statistic 0.273 from the preceding table answers a different question and must not replace this comparison.
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