Question 1

Psychology majors at the state college consist of 40% males and 60% females. The psychology department is conducting a survey of its majors and obtains a sample by randomly selecting students so there will be 20 males and 30 females from the list of psychology majors. What kind of sampling is used in this example?

Accepted Answer

This is an example of proportionate stratified random sampling because the sample size for each gender group is proportionate to the population size of each group in the psychology major.

Question 2

A teacher obtains a sample of children from a fifth-grade classroom by randomly selecting the third, fifth, and eighth rows and taking all the students in those rows. This is an example of ____ sampling.

Accepted Answer

This is an example of cluster sampling because the teacher selected entire rows (clusters) instead of individual students.

Question 3

A sample consists of 25 freshmen, 25 sophomores, 25 juniors, and 25 seniors from a local high school that has an equal number of students in each class. If the sample was obtained using a list of all the students in the high school, it is probably an example of ____ sampling. If the sample was obtained without a list of students, it is likely an example of ____ sampling.

Accepted Answer

The first scenario describes stratified random sampling because the sample includes equal numbers from identifiable subgroups (freshmen, sophomores, juniors, seniors), ensuring representation from each group. The second scenario suggests quota sampling, a non-probability sampling technique where the selection is made to reflect certain characteristics of the population, in this case, class year, but without using a list for random selection.

Question 4

One criticism of proportionate stratified random sampling is that ____.

Accepted Answer

Proportionate stratified random sampling is designed to ensure that each subgroup in the population is represented in the sample in proportion to its size in the population. However, this may result in some subgroups having a very small representation in the sample which can impede statistical analysis. It is important to ensure that subgroups are not too small and that statistical analysis can still be conducted effectively.

Question 5

How does convenience sampling compare to probability sampling?

Accepted Answer

Convenience sampling is faster than probability sampling because it involves selecting participants who are easily accessible or readily available, whereas probability sampling requires a more rigorous process of randomly selecting participants from a larger population. However, convenience sampling is generally less reliable and more vulnerable to bias than probability sampling.

Question 6

The workers in a factory are organized into five-person teams. When conducting a work-environment survey, a researcher randomly selected 10 teams to obtain a total sample of 50 workers. The researcher used ____ sampling.

Accepted Answer

The researcher used cluster sampling as the workers were already organized into teams, and the researcher randomly selected 10 teams to obtain a sample of 50 workers. Therefore, the teams were the clusters in this sampling technique.

Question 7

One criticism of a stratified random sample is that ____.

Accepted Answer

While a stratified random sample is based on a random selection process, the criticism is that the sample may not be representative of the population. This is because the stratification process can introduce bias if the strata do not accurately reflect the population. Additionally, some segments of the population may be underrepresented or not represented at all if they are not included in any of the strata. However, a stratified random sample can still provide more precise estimates for subgroups of the population than a simple random sample.

Question 8

Which sampling technique is most likely to result in a biased sample?

Accepted Answer

Convenience sampling is most likely to result in a biased sample because it involves selecting individuals who are easily accessible or convenient to the researcher. This can lead to an unrepresentative sample that does not accurately reflect the entire population of interest. The other sampling techniques listed involve more rigorous and systematic methods to ensure that the sample is representative of the population.

Question 9

The technique of quota sampling is most similar to ____ sampling.

Accepted Answer

Both quota sampling and stratified random sampling involve dividing the population into subgroups and then selecting participants from each subgroup. However, in quota sampling, the researcher sets a specific number of participants to be selected from each subgroup, whereas in stratified random sampling, the number of participants selected from each subgroup is based on the proportion of that subgroup in the population.

Question 10

A professor teaching an introductory psychology class of 200 obtains a sample of 25 students by selecting every eighth name from the class list. The professor is using ____ sampling.

Accepted Answer

The professor is using systematic sampling, which involves selecting individuals from a population at fixed intervals, in this case every eighth name from the class list. It is not simple random because not every individual in the population has an equal chance of being selected, and it is not convenience sampling because the professor is not selecting individuals based on ease of availability or willingness to participate. It is also not proportionate stratified random sampling because the sample is not proportionally representative of different subgroups within the population.

Question 11

A researcher recruits a sample of 25 preschool children for a research study by posting an announcement in a local daycare center describing the study and offering a $10 payment for participation. What kind of sampling is the researcher using?

Accepted Answer

The researcher is using convenience sampling by recruiting children who are easily accessible through the local daycare center and using a monetary incentive as motivation to participate.

Question 12

The primary advantage of a stratified random sample is that it ____.

Accepted Answer

Stratified random sampling ensures that each subgroup (stratum) of the population is adequately represented, which helps in obtaining sufficient sample sizes for statistical analysis of each group.

Question 13

Quota sampling produces the same advantages for convenience sampling that ____ sampling produces for probability sampling.

Accepted Answer

Stratified random sampling is a probability sampling technique that divides the population into homogeneous groups, called strata, and selects a random sample from each group. Quota sampling is a non-probability sampling technique that also divides the population into homogeneous groups, but the researcher selects a predetermined number of participants from each group instead of randomly selecting them. By using quota sampling, the researcher can obtain a sample that is more representative of the population, similar to using stratified random sampling. Therefore, quota sampling produces the same advantages for convenience sampling that stratified random sampling produces for probability sampling.

Question 14

A researcher wants to obtain a sample of 30 preschool children consisting of 10 two-year-old children, 10 three-year-old, and 10 four-year-old children. Assuming that the children are obtained from local daycare centers, this researcher should use ____ sampling.

Accepted Answer

The answer of A researcher wants to obtain a sample...

Question 15

A researcher would like to describe and compare the attitudes of four different ethnic groups of students at a local state college. To obtain participants for the study while ensuring sufficient numbers of participants from each of the ethnic groups, the researcher should probably use ____ sampling.

Accepted Answer

Stratified random sampling ensures that participants are selected from each ethnic group in proportion to their representation in the population. This will provide a representative and sufficient sample from each group for comparison.

Question 16

A researcher would like to examine the political attitudes for students at a local university. The researcher will evaluate a sample of 200 students but would like to be sure that the ages and genders of individuals in the sample accurately represent the ages and genders for the entire student body at the university. What would be the best sampling method for the researcher to use?

Accepted Answer

Proportionate stratified random sampling would be the best sampling method for this scenario as it ensures that the sample accurately represents the population in terms of age and gender. The researcher can create strata based on age and gender, and then randomly select participants from each stratum in proportion to their representation in the larger population. This will help ensure that the sample is not biased towards certain age or gender groups and provides a representative sample for the research.

Question 17

A cluster sample usually does not qualify as a true random sample because ____.

Accepted Answer

The answer of A cluster sample usually does not qualify...

Question 18

The most commonly used sampling method in psychological research is probably ____ sampling.

Accepted Answer

Convenience sampling is the most commonly used method in psychological research because it involves selecting participants who are easily accessible to the researcher, making it a practical and cost-effective approach.

Question 19

A researcher would like to select a sample of 50 people so that five different age groups are equally represented in the sample. Assuming that the researcher does not know the entire list of people in the population, which sampling technique should be used?

Accepted Answer

Quota sampling allows the researcher to ensure that specific quotas for various subgroups (in this case, age groups) are met, which is suitable when the researcher aims for equal representation without needing a full list of the population.

Question 20

A systematic sample does not qualify as a true random sample because ____.

Accepted Answer

Systematic sampling does not qualify as a true random sample because the selections are not independent of each other. Once the first element is chosen randomly, subsequent elements are selected through a fixed interval, making the selections dependent on the first choice.

Quiz 5: Selecting Research Participants