General questions for chapter 14 (heterogeneity)

[A.Wittich]

I was wondering if somebody can clarify some bits and pieces concerning the heterogeneity part of chapter 14.
1. By eliminating the interaction terms of encounter group and time the model bht is working. But I think the columns in the text (B10 →B13) are wrong considering the DM shown in the picture and should be B21→B27?
2. I do not understand what model {N, pa(t) = ca(t) = pb(t) + z = cb(t) + z } means? I get that the behavior aspect is gone hence p=c (for two mixtures, hence subscription with a and b) which also can vary with time, but what does the “z” mean? Apparently to get that model only the encounter group column needs to be deleted but I was wondering if the three term interaction (h.t.encgrp) needs to be deleted too as we don’t have the encounter group anymore?

I am very grateful for clarification! Thank you very much in advance. Anja

[Paul Lukacs]

1. Columns B10->B13 are definitely wrong in the text. B21->B27 will eliminate the encounter group by time interaction, but you'll probably also want to eliminate the 3-way interaction as well (columns B28-35).

2. z is the additive difference between capture probability in the two mixtures. Yes, the 3-way interaction should be deleted here also.

Paul

[cooch]

1. Columns B10->B13 are definitely wrong in the text. B21->B27 will eliminate the encounter group by time interaction, but you'll probably also want to eliminate the 3-way interaction as well (columns B28-35).

2. z is the additive difference between capture probability in the two mixtures. Yes, the 3-way interaction should be deleted here also.

Paul

Both changes have been made in the version of Chapter 14 that is currently online.