homework questions 83

Q2-5

please do what you can do

2.Install the R Package faraway. Consider the esdcomp data that were recorded
on 44 doctors working in an emergency service at a hospital to study the
factors affecting the number of complaints received. Build a model for the
number of complaints received and report your conclusions.
3. The bootstrap is a general tool for assessing statistical accuracy. Describe
the bootstrap in general and then for a particular example of your choosing.
4. Cross validation is probably the simplest and most widely used method for
estimating prediction error. Ideally if we had enough data, we would set
aside a validation set and use it to assess the performance of our model.
Since data are sometimes scarce, this may not always be possible. We
finesse this problem by using K-fold cross-validation. Explain.
5. For the analysis of count data most statistical software packages now offer models designed to deal with the situation where there is an excessive
number of 0 counts.
(a) Discuss the various potential sources of zeros.
(b) Describe mixture and two-part models and how they each deal with the
different types of zeros.