Question

List and describe the four methods of surveying sample population, use your own definition, and provide an example for each.

Answer 1

Methods of surveying

Sampling methods are divided into 2.

a, Probability samples

b, Non-Probability samples

Probability samples

It has a non-zero chance of being chosen for the sample. In this case we can't be sure that each population element has a non-zero chance of being chosen

There are 5 types of probability sampling method . They are

a, Simple Random Sampling

b, Stratified Sampling

c, Cluster Sampling

d, Multistage Sampling

e, Systematic Random Sampling

Main advantage of the probability sampling methods is that, it guranteed the sample chosen is from the population. It ensures that the statistical conclusion will be correct.

a, Simple Random Method.

It has many ways to obtain a simple random sample. One is lottery method, from the N population members, the numbers are placed in bowl and thoroughly mixed. Then anyone can select from this bowl. The selected numbers are included in the sample.

eg: suppose the population is alphabetic letters from A to T. In from this letters we taken some samples by random. That is C, J, G, M, Q

Selected without any specility.

b, Stratified Sampling.

Based on some characteristics the peoples are divided into groups. From in the each group a sample is selected. In the stratified sampling, the groups are called strata. eg : The total peoples are A to Z. Then it will divided into strata, that is 1st group is A to E, 2nd group is F to J, 3rd group isK to O, 4th group isP to T, 5 th group isU to Z. Selected are from these each group is C, H, L, S, W.

c, Cluster sampling.

In the cluster sampling, each member of the population is assigned to comparable group. Each group is called a cluster, l. A sample of cluster is chosen from the simple random sampling. In the cluster sampling, the sample includes elements only from sampled clusters. eg: we take total populations are numbers, from 1 to 20. It divided by comparable groups. Firstly odd numbers: 1,3,5,7,9,11,13,15,17,19. Then the even numbers: 2,4,6,8,10,12,14,16,18,20. The selected clusters are 5,11,2,14,19,8

d, Multisage sampling.

In this case we select a sample by using combinations of different sampling methods. eg: They might randomly choose a certain number of area, codes or phone numbers etc.