Modern Actuarial Risk Theory

| 1. | Of the distributions mentioned in the random component of a GLM, give the density (including the range), the mean and the variance. |
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| 2. | Show that if X i ~ gamma( ?, ? i) with parameters ? = 1/ ? and ? i = 1/( ? ? i), all X i have the same coefficient of variation, i = 1, , n. What is the skewness? |
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Answers
| 1. | ? i, ? i; ? i; ? i; ? i ? i |
| 2. | Coefficient of variation: s.d./mean = = |
| 1. | Verify (8.4), (8.16) and (8.17). Also verify if (8.11) describes the maximum of (8.13) under assumption (8.14). |
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| 2. | Show that the methods of Bailey-Simon, marginal totals and least squares, as well as the direct method, can all be written as methods of weighted marginal totals, where the following system is to be solved: ![]() |
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| 3. | Show that the additive model E[ X ij] = ? i + ? j, of the least squares method coincides with the one of the marginal totals. |
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| 4. | Which requirement should the means and variances of Y ij/( ? i ? j) fulfill in order to make (8.17) produce optimal estimates for ? i? |