Question

A) Distinguish between nonprobability and probability samples and compare their advantages and disadvantages.

Which are used for qualitative and which for quantitative studies?

1) Identify and describe two types of non-probability sampling methods and two types of probability sampling methods

2) Discuss how sample size requirements differ between qualitative and quantitative studies.

B) Identify phenomena/variables that lend themselves to self-reports, observation, and biophysiologic measurement and discuss each of these types of data collection.

Answer 1

Note : One question only can be answered in one post.

Distinguish between nonprobability and probability samples and compare their advantages and disadvantages.

Probability sampling is a method in which each members of the population has an equal probability of getting selected in the sample.
Example are
Simple Random Sampling
Stratified Sampling
Cluster Sampling
Systematic Sampling

In Non probability sampling all the members of the population do not have an equal chance of getting selected in the sample.
Here the selection is done basis the judgment or application of practical knowledge of the reseracher.

Example are
Convenience Sampling
Quota Sampling
Judgment or Purposive Sampling
Snowball Sampling

Probability sampling is implement where the reserach is experimental in nature or the reserach wants to prove a hypothesis. In case of exploratory reserach non probability sampling employed.

Due to the nature of non probability sampling, bais is introduced in the results, where as in probability sampling the results are bias free.

Since the sample is random taken in the probability sampling the results can be extended to the population but it is not possible in non probability sampling.