IAI Actuarial Core Principles · Actuarial Statistics · Generalised linear models
Which statement about the components of a GLM is correct?
The linear predictor is linear in the parameters, and the link function connects it to the expected value of the response, g(μ)=η. The link is not a transformation of the observations, and the response need not be normal.
- AThe linear predictor must be linear in the covariates' parameters, and the link function relates it to the mean of the responseCorrect
- BThe response must be normally distributed with constant variance
- CThe link function transforms the response observations before fitting
- DThe linear predictor must be linear in the covariates themselves, so x² terms are not allowed
- The link function must always be the identity for the exponential family
Explanation
A GLM requires linearity in parameters, so terms like x² are allowed. The link g relates the mean μ to η, g(μ)=η; it does not transform the observations. The response comes from an exponential family, not necessarily normal.
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