Question 1

Interviewing individuals at a neighborhood café can generate a judgment sample.

Accepted Answer

The answer of Interviewing individuals at a neighborhood café can...

Question 2

Cluster sampling is an example of a nonprobability sampling method.

Accepted Answer

Cluster sampling is a probability sampling method where the population is divided into clusters, and a random sample of these clusters is selected for study.

Question 3

For a given level of precision and confidence level, a researcher determines that he needs a sample size of 400. The study was to find out that the proportion of people who smoke is 30 percent. For the same level of precision and confidence, she would have needed the same sample size if the proportion of those who smoked were to change to:

Accepted Answer

The answer of For a given level of precision and...

Question 4

A defined target population consists of the complete group of elements that are identified for investigation based on the objectives of the research project.

Accepted Answer

A defined target population refers to a specific group of individuals or elements that are precisely identified for research purposes based on the research objectives.

Question 5

The first step in drawing a systematic random sample is to obtain a list of potential sampling units that contain an acceptable frame of the target population elements.

Accepted Answer

This is correct. In order to draw a systematic random sample, a list of potential sampling units must be obtained to form a frame of the target population elements.

Question 6

Which of the following statements is true about sample size formula for nonprobability samples?

Accepted Answer

Sample size formulas are typically used for probability samples to ensure representative and reliable results. Nonprobability samples, on the other hand, do not have a known sampling frame or a way to control for selection bias, making it difficult to calculate an appropriate sample size. Therefore, sample size formulas cannot be used for nonprobability samples.

Question 7

A census is less time-consuming and less costly than a sample.

Accepted Answer

A census requires gathering data from every individual or item in a population, which can be time-consuming and costly. A sample, on the other hand, can provide reliable information with a smaller subset of the population while saving time and resources. Therefore, a census is generally considered more costly and time-consuming than a sample.

Question 8

Any geographical unit with identifiable boundaries can be used in area sampling.

Accepted Answer

Area sampling is a method of random sampling where geographical areas are chosen as the sampling units. These areas should have clearly identifiable boundaries to ensure proper sampling coverage. Therefore, any geographical unit with identifiable boundaries can be used in area sampling.

Question 9

The skip interval in systematic random sampling is computed by dividing the number of potential sampling units on the list by the desired sample size.

Accepted Answer

The skip interval represents the number of sampling units that are skipped between each selected unit. It is calculated by dividing the population size by the desired sample size. In systematic random sampling, after selecting the starting point randomly, every nth unit is selected based on the skip interval.

Question 10

Simple random sampling usually produces biased estimates of a population's characteristics.

Accepted Answer

Simple random sampling is actually considered to be one of the most unbiased sampling techniques. It involves randomly selecting individuals from the population, giving each individual an equal chance of being selected. However, sampling bias can occur if the sample does not represent the true population, or if there is nonresponse bias (when selected individuals do not participate in the study).

Question 11

Another term for judgment sampling is purposive sampling.

Accepted Answer

Judgment sampling and purposive sampling are two terms used interchangeably to describe a non-probability sampling method where the researcher selects a sample based on their judgment or purposeful criteria.

Question 12

Disproportionate stratified sampling is used when the target population produces sample sizes for subgroups that differ from their relative importance to the study.

Accepted Answer

Disproportionate stratified sampling is indeed used when the target population produces sample sizes for subgroups that differ from their relative importance to the study. This sampling method selects larger samples from subgroups that are critical to the research question or are expected to have higher variability, while reducing the sample size from less important subgroups. This approach ensures more precise estimates of population parameters, and it is beneficial when resources are limited, and researchers need to optimize their sampling strategy.

Question 13

The U.S. census is conducted every five years.

Accepted Answer

The U.S. census is conducted once every 10 years. The last census was conducted in 2020, and the next one will be in 2030.

Question 14

Systematic random sampling works better than simple random sampling especially in those situations where there might be a hidden pattern in population.

Accepted Answer

The answer of Systematic random sampling works better than simple...

Question 15

In order to determine the proportion of people who favor imposing sales tax for all Internet purchases, the minimum sample size needed for a precision level of 5 percent and a confidence level of 95 percent, is:

Accepted Answer

To calculate the sample size needed, we can use the following formula:

n = (Z^2 * p * q) / d^2

Where: 
Z = the Z-score for a 95% confidence level, which is 1.96 
p = the estimated proportion of people who favor imposing sales tax for all Internet purchases (we don't know this, so we can use 0.5 for a conservative estimate) 
q = 1 - p 
d = the desired precision level, which is 0.05

Plugging in the values:

n = (1.96^2 * 0.5 * 0.5) / 0.05^2 
n = 384.16

Rounding up to the nearest whole number, we get a sample size of 384. Therefore, the best choice is C.

Question 16

Referral sampling involves identifying a set of respondents who can help the researcher identify additional people to include in the study.

Accepted Answer

Referral sampling involves asking respondents to provide names of other individuals who might be willing to participate in the study, thus expanding the participant pool.

Question 17

In which stage of the sampling plan will random-digit dialing probably be considered?

Accepted Answer

The answer of In which stage of the sampling plan...

Question 18

Sampling errors are related to the accuracy of data whereas nonsampling errors relate to the representativeness of the sample to the defined target population.

Accepted Answer

Sampling errors are related to the representativeness of the sample, while nonsampling errors are related to the accuracy and precision of data collection and processing.

Question 19

If the estimated population proportion is .30 based on previous studies, and the acceptable error is plus or minus 5 percent, and the z-value for a 95 percent level of confidence is 1.96, the needed sample size is approximately:

Accepted Answer

The sample size (n) can be calculated using the formula: n = (Z^2 * p * (1-p)) / E^2, where Z is the z-value, p is the estimated population proportion, and E is the acceptable error. Plugging in the values: n = (1.96^2 * 0.30 * 0.70) / 0.05^2 ≈ 323.

Question 20

A voters list is an example of a sampling frame.

Accepted Answer

A voters list is a complete list of all eligible voters in a given area and therefore serves as a sampling frame for selecting a random sample of voters for surveys or research purposes.

Quiz 6: Sampling: Theory and Methods