Chapter 9

Question 1

What is the population and census in sampling?

Answer 1

Population: entire group under study as defined
by research objectives.

Census: accounting the complete population. It
requires information from everyone in the population

Question 2

What is a sample, sample unit, and sampling error?

Answer 2

Sample: subset of the population that should represent the entire group

Sample unit: the basic level of investigation

Sampling error: any error in a survey that occurs because a sample is used

Question 3

What is sample frame and sample frame error?

Answer 3

Sample frame: list of people in population that can be sampled

Sampling frame error: the degree to which the sample
frame fails to account for all of the population

Question 4

What are probability samples and its methods?

Answer 4

Probability samples: members of the
population have a known chance (probability) of being
selected into the sample

Probability sampling methods:
* Simple random sampling
* Systematic sampling
* Cluster sampling
* Stratified sampling

Question 5

What are non-probability samples and methods?

Answer 5

Non-probability samples: chances (probability) of selecting members from the population into the sample are unknown

Non-probability methods:
- Convenience sampling
- Chain referral sampling
- Purposive sampling
- Quota sampling

Question 6

Define simple random sampling

Answer 6

Probability of being selected into the sample is “known” and equal for all members of the population. Common method is random digit dialing.

Probability of selection = sample size / population size

Question 7

What is systemic sampling?

Answer 7

Systematic sampling: Way to select a random sample
from a directory or list that is much more efficient than
simple random sampling

• Uses a skip interval for selection

Question 8

What is cluster sampling?

Answer 8

Method where population is
divided into subgroups, called “clusters,” each of which could represent the entire population

• Area sampling is form of cluster sampling (geographic area divided into clusters)

Question 9

What is stratified sampling?

Answer 9

Stratified Sampling: separates the population into different subgroups and then samples all of these subgroups

• Used when working with “skewed” population

Question 10

Describe convenience samples and chain referral samples

Answer 10

Convenience samples: samples drawn at the
convenience of the interviewer (mall interviews) in high-traffic location

Chain referral samples: require respondents to provide the names of prospective respondents.

Question 11

Describe purposive samples and quota samples

Answer 11

Purposive samples: requires a judgment or an “educated
guess” of who should represent the population

Quota samples: specified percentages of the total sample for various types of individuals to be interviewed

Question 12

Describe 3 online sampling techniques

Answer 12

1. Online panels: large numbers of individuals who agreed to participate in online surveys
2. River samples: created via use of banners, pop-ups,
   or other online devices that invite website visitors to take part in the survey
3. E-mail list samples: purchased or procured from someone or some company that has compiled email
   addresses of opt-in members of the population of interest

Question 13

What are the steps in a sample plan?

Answer 13

1. Define the population
2. Obtain sample frame
3. Decide sample method
4. Decide sample size
5. Draw the sample
6. Validate the sample