Table 4.

Fitness associations with absolute endocranial volume: results from the lifetime breeding success (males and females) and lifetime reproductive success (females) models for adults (3+ years of age, EV = endocranial volume, means in millilitres for EV and millimetres for jaw length, a t-statistic for female LBS and a z statistic for other models were automatically determined by R and depended on whether the standard errors were known, bold and italic = significant). (GLMs consisted of LBS or LRS as the response variable and endocranial volume and jaw length as fixed effects. The male LBS model had a negative binomial distribution and a log link; the female LBS model had a quasi-Poisson distribution with a log link because it was overdispersed; and the female LRS model had a Poisson distribution with a log link.)

absolute endocranial volumejaw length
modelNestimates.e.t/zp-valueestimates.e.t/zp-value
LBS male1660.0030.0090.310.760.090.024.10<0.001
LBS female2440.0010.0011.020.310.020.0034.96<0.001
LRS female2440.0040.0022.170.030.020.0045.61<0.001