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# Form 1 Geography Online Lessons on Statistics

In this lesson we are going to learn about data collection methods including counting, photographing, digging, sample collection and its types

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6. Collecting Samples
-Getting a small part e.g. of soil, rock or vegetation to represent the whole to be used to carry out tests in the laboratory.
7. Counting/census taking
- Arithmetical counting and recording.
8. Photographing
- Capturing on film or video and still photographs.
9. Digging
- Using tools such as hoe pick axe, spade or soil auger to get samples of soil and rocks. 10. Feeling and touching
- Using fingers to feel the surfaces of soils and rocks to get their textures.
11. Sampling
- Examining by taking a sample -a part representing the whole (population).
Types of Sampling
1. Random Sampling
- Selection of members of a group haphazardly where every item has an equal chance of being selected e.g. to select 5 students to go for a tour from a class:
• Class members write their names on pieces of paper
• They are folded and put in a basket
• The basket is shaken and fives papers are taken out
2. Systematic Sampling
-Selection of members of a sample from an evenly distributed phenomena at regular intervals e.g. after every 10 items/members.
3. Stratified sampling
-Selection of members of a sample by breaking the population into homogenous groups e.g. to select 6 students to go for a tour:
• Break the class into boys and girls
• Select 3 student from each group by random or systematic sampling
• Combine units from each group to form the required sample.
4. Cluster Sampling
-Selection of sample by dividing the sample into clusters with similar characteristics then a sample is taken from each cluster and representative choices from each cluster are combined to form a sample e.g. to sample the housing cost an estate is chosen to represent each group and representative choices are chosen from each estate and combined to form a sample.
a) It’s less expensive
b) It saves time
c) It avoids bias
b) Systematic sampling can only be done to an evenly distributed population Experimentation
– Conducting a test or investigation to provide evidence for or against a theory e.g. to determine the chemical composition of rocks and soils.