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. 2009 Feb 3;6:4. doi: 10.1186/1742-9994-6-4

Table 2.

GLM models illustrating how other hypotheses about killer whale reproduction were evaluated.

Comparison Error Model n nA BIC Pr [M|Y]
Repro. lifespan Gaussian Null 21 751.2 0.824
Repro. lifespan Gaussian mom's survival status 21 11 754.3 0.176
IBI Poisson Null 62 107.1 0.645
IBI Poisson mom's survival status 62 28 108.4 0.345
juvenile φ(1–5) Binomial Null 890 419.4 0.963
juvenile φ(1–5) Binomial grandma's survival status 890 674 426.6 0.027
juvenile φ(1–5) Binomial grandma's survival status + maternal age 890 432.9 0.001

This table includes comparisons for reproductive lifespan, females' interbirth intervals, and survival of grandoffspring (φ). In each case, the null model is the simplest possible (grandmothers have no effect). The sample size for each comparison (n) represents the number of whales, except in the case of juvenile survival, where it represents whale-years (an individual may be recorded for several years). The subset of sample size with grandmothers alive is also included (nA).