unseen fieldwork

Primary data

Data you collect yourself

Secondary data

Data collected by someone else

Quantitative data

Data that is statistical/numbers

Qualitative data

Data that is descriptive

Examples of quantitative data

Physical- river depth, pebble size, erosion rates

Human- EQS, traffic counts, pedestrian counts

Examples of qualitative data

Physical- photographs, pebble roughness

Human- interviews, questionnaires, OS maps

What is random sampling?

Randomly choosing sites to collect data

What is systematic sampling?

Picking sites every X metres

What is stratified sampling?

Picking sites by topic

Advantages of random sampling

• not biased- each site has an equal chance of being picked.

• Can easily done with a large area.

Disadvantages of random sampling

• sites can get clustered together meaning data collection isn’t representative.

• May lead to sites that are inaccessible.

Advantages of systematic sampling

• gives a good representation of an area.

• Easier to do than random sampling.

Disadvantages of systematic sampling

• can be time consuming.

• Can be bias as not all sites have an equal chance of being selected.

Advantages of stratified sampling

• flexible- fits with a lot of different enquiries

• Gives a good comparison of different areas (eg upper, middle, and lower course of a river)

Disadvantages of stratified sampling

• not suitable for something like a questionnaire.

• Could lead to bias from the person picking the sites.

Give advantages and disadvantages of traffic counts

Adv:

• understand how busy/popular an area is.

disadv:

• can easily miscount by mistake if an area is really busy.

Give advantages and disadvantages of environmental quality surveys.

Adv:

• gain info on a wide variety of factors.

• Number is easy to compare scores.

Disadvantages:

• subjective- based on opinion so can be bias.

What are the two ways we aim to improve data collection methods?

1. make it accurate and reliable.

2. Make it reprasentative

Give 3 ways we can make our collection methods more ACCURATE & RELIABLE.

1. COLLECT MORE DATA & GENERATE AN AVERAGE -THIS REDUCES THE RISK OF ANOMALIES.

2. COLLECT DATA AT DIFF DAYS/TIMES/WEATHER.

3. ASK A WIDER VARIETY OF QS ON QUESTIONNAIRE.

Give 3 ways we can make our data collection methods more REPRASENTATIVE.

1. COLLECT DATA AT MORE SITES TO COVER A LARGER AREA, REDUCING RISK OF ANOMALIES.

2. ASK LOTS OF DIFF PEOPLE FOR A QUESTIONNAIRE TO COVER ALL AGES/GENDERS/ETHNICITIES.

3. COLLECT DATA AT DIFF TIMES/DAYS/WEATHER.

What is a choropleth map?

a map that uses different shades of colour/symbols to display different amounts

What is an isoline map?

A map that joins together values of the same value (eg contour lines)

Advantages of choropleth maps

Easy to spot general trends

Disadvantages of choropleth maps

• not useful for showing total values

Advantages of pie charts

• Easy to interpret as percentages are represented as segments of one whole.

Disadvantages of pie charts

• can not be used to show trends