代写data留学生、MLR代做、代写Python/c++/Java程序设计

日期：2019-05-20 11:20

Question 2

The data for this question comprises measurements on breeding pairs of land-bird species collected

from 16 islands around Britain over the course of several decades available in a .csv le, bird. For

each species, the data set contains an average time of extinctions, extinct, on those islands where

the species appeared. (This is actually the reciprocal of the average of 1/T where T is the length of

time the species remained on the island and 1/T is taken to be zero if the species did not become

extinct on the island); the average number of nesting pairs per year, over all islands where the species

appeared (nest.pair); the size (size) of the species, (S = Small, L = Large); and the migratory

status (mig.status) of the species, (R = Resident, M = Migrant). It is expected that species

with large numbers of nesting pairs will tend to remain longer before becoming extinct. Of particular

interest is whether, after accounting for the number of nesting pairs, size or migratory status has any

eect.

(a) Fit a multiple linear regression (MLR) model with extinct as the response variable and all

other covariates as predictors. Is the regression model signicant? Interpret the coecients

for the categorical variables in this model. Does the coecient support the expectations that

large number of nesting pairs tend to delay extinction?

(b) As the question indicates, of particular interest is whether, after accounting for the number

of nesting pairs, size or migratory status has any effect. Conduct a formal test of the

hypothesis that βSize= βMigStatus= 0 using an appropriate anova table. Evaluate the Fstatistic

and the corresponding p-value.

(c) The Red-crested Periwinkle is a small, migratory species of bird, while the Great Plover isa

large, resident species of bird. Assuming that the number of nesting pairs is thesame for each

species over the period, based on the model in part (a), what would you predict the di

erence in extinction times to be for these two species?

(d) A noted theory suggests that Size and Migratory Status should contribute equally to the

extinction time. Test whether the coecients of size and mig.status are the same.

Construct an appropriate model to test this hypothesis.

(e) Produce the appropriate diagnostic plots for the model tted in part (a) and as-sess the

model assumptions. Produce the relevant in

uence diagnostics for this model. Which data

pointsappear to bein

uential in theanalysis,and in what sense would you consider them in

-

uential? Also, do any points appear to be outliers? If so, to which species do these points

correspond?

(f) Two transformations are suggested for the response variable, log(extinct) and 1/

extinct. Investigatewhether using thesetransformationsimproves on themodel t. Comment

on theassumptions of MLR forthesemodelsas compared to your originalmodel. Which

of three models would you choose based on your analysis?

Assignment 2 - Sem 1, 2019 Page 3 of 3