The Russians Are the Fastest in Marathon Cross-Country Skiing: The “Engadin Ski Marathon”

Table 2

Coefficients () and standard errors (SE) from multivariate regression models for age by sex and nationality.

Parameter		SE
Intercept	43.54	0.04	<0.001
Nation	0.36	0.01	<0.001
Sex = women	−6.44	0.10	<0.001
Sex = men	0	0
Sex = Women × nationality	0.23	0.03	<0.001
Sex = men × nationality	0	0

This parameter was set to zero because it was redundant.