# Practical advice

David L Miller & Jason J Roberts

## Real survey data is messy

### Collecting and analysing data in the real world

- We've talked a lot about models
- We've also talked about assumptions
- Our example is relatively well-behaved
- What can we do about all the nasty real world stuff?

### Aims

- Here we want to cover common questions
- Not definitive answers
- Some guidance on where to look for answers

## What should my sample size be?

### What do we mean by "sample size"?

- Number of animal (groups) recorded
- Number of segments
- Number of segments with observations

### How would we know when we have enough samples?

- We don't
- Heavily context-dependent
- Go back to assumptions