Homework Answers

• To Worksheet X in the booklet

Data Collection Methods

Aims: •To know the advantages and disadvantages of different sampling techniques and be able to apply them to the Geography IA

Recap…

• We need to find out how the height of buildings (number of floors) changes as you move from the PLVI to the rural-urban fringe in HK

• What PLVI shall we use? How did you decide?• Last lesson we agreed on 3 transects through HK

(we’ll see them later)• When going along the transects how should we

select buildings to include in our sample?

Random Sampling

• In a random sample every building in the study area has an equal chance of being picked.

• So is probably not as simple as you might think• You would first need to identify each building

in the sample area, allocate it a number and then pull out the numbers at random

Random Sampling

• What are the benefits and problems of using this technique?

Advantages Disadvantages

Systematic Sampling

• Systematic sampling is when buildings are chosen at regular intervals, e.g. every 400m

• What are the benefits and problems of this option – specifically for our study?

Advantages Disadvantages

Stratified Sampling

• If you know there are important sub-groups in the sample area (e.g. CBD, inner city, inner suburbs, etc) you can select a sample that ensures each sub-group is represented fairly

• What are the benefits and problems of using this technique?

Advantages Disadvantages

Finalising our Method

• The three transects are:

Transect 1: Nathan Road

Transect 2: Chatham Road

Transect 3: Queensway

However…

• How should we select which buildings to count in our sample?

• Now let’s organise you into groups and decide which transect you will work on

• Before we finalise the details, how many buildings will we need in our sample to make it statistically reliable?

To the computer room…• What we need to decide:

– How far is it from one end of the transect to the other?

– How many intervals should you have? – Therefore, how far apart will the intervals

be? – Therefore, specifically, where will the

intervals be? – How many buildings either side of the

transect should we include in the sample? – How should we decide which buildings?

Homework

• Complete Worksheet X in the booklet by next lesson

What do the pictures mean?

I’m teaching – listen!

Try to answer questions if you can

Work in silence

You can discuss the work

Work in a group