Question

1. Choose one design method from the list below. Using your example, make a list of 2 or 3 advantages and 2 or 3 disadvantages for using the method.
   • Cluster sampling
2. The name of each student in a class is written on a separate card. The cards are placed in a bag. Three names are picked from the bag. Identify which type of sampling is used and why.
3. A phone company obtains an alphabetical list of names of homeowners in a city. They select every 25th person from the list until a sample of 100 is obtained. They then call these 100 people to advertise their services. Does this sampling plan result in a random sample? What type of sample is it? Explain.
4. The manager of a company wants to investigate job satisfaction among its employees. One morning after a meeting, she talks to all 25 employees who attended. Does this sampling plan result in a random sample? What type of sample is it? Explain.
5. An education expert is researching teaching methods and wishes to interview teachers from a particular school district. She randomly selects 10 schools from the district and interviews all of the teachers at the selected schools. Does this sampling plan result in a random sample? What type of sample is it? Explain.

Answer 1

(a)

(i)   Type of Sampling: Simple Random Sampling

(ii)

Advantages: The Sample will represent the target population. This eliminates bias

Disadvantages: It is very difficult to achieve (time, effort, money etc.)

(b)

(i)   Type of Sampling: Systematic Sampling

(ii)

This Sampling Plan does not result in a random sample. Systematic Sampling is preferable to Simple Random Sampling when there is a low risk of data manipulation.

(c)

(i)   Type of Sampling: Convenience Sampling

(ii)

This Sampling Plan does not result in a random sample, since Convenience Sampling is non - probability sampling that involves the sample being drawn from that part of the population that iscloseto hand.

(d)

(i)   Type of Sampling: Cluster Sampling

(ii)

This Sampling Plan does not result in a random sample. Cluster Sampling is preferred in situations when mutually homogeneous yet internally heterogeneous groupings are evident in a population.