M3S2 Department of Mathematics Question Q 1 Q 2 Q 3 Statistical Modelling II Examiner's Comments The earlier parts were well-answered. The relationship between variance and leverage was generally not well known. Cook's distance was only rarely used to comment on changes to the model fit. The lack of symmetry about zero in the residual plot was mentioned by only very few candidates. Generally well done, though the calculations with the inverse Gaussian deviance were generally messier than necessary, as typically the exponential family form of the likelihood was used - cancellations are more obvious in the form that was given in the paper. Generally well done - the last past was found difficult, although there were a number of complete answers. The parametric bootstrap was well-known, although many thought that mean(ds <0.00001) was a p-value. Goodness of fit was not really understood, and relatively few candidates picked out useful parts of the output. Q 4 Printed: 27/07/2018 11:48:06 M4S2 Department of Mathematics Question Q 1 Q 2 Q 3 Statistical Modelling II Examiner's Comments The earlier parts were well-answered. The relationship between variance and leverage was generally not well known. Cook's distance was only rarely used to comment on changes to the model fit. The lack of symmetry about zero in the residual plot was mentioned by only very few candidates. Generally well done, though the calculations with the inverse Gaussian deviance were generally messier than necessary, as typically the exponential family form of the likelihood was used - cancellations are more obvious in the form that was given in the paper. Generally well done - the last past was found difficult, although there were a number of complete answers. The parametric bootstrap was well-known, although many thought that mean(ds <0.00001) was a p-value. Goodness of fit was not really understood, and relatively few candidates picked out useful parts of the output. Q 4 Some good understanding was shown. The last parts of the question were not answered well.Q 5 Printed: 27/07/2018 11:48:06
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