Question 1

Jake's research methods instructor asks him to conduct a survey on "cheating" with a random sample of graduate students.To save time,he goes to the cafeteria and distributes the survey questionnaires among the students present there.In this case,the sampling method used by Jake is called _____ sampling.

Accepted Answer

Haphazard sampling, also known as convenience sampling, involves selecting participants based on their availability and accessibility, which is what Jake did by distributing the questionnaires among the students present in the cafeteria. This method is quick and easy but is not a representative sample of the entire population. If Jake wanted a representative sample, he should have used a random sampling method such as simple random, stratified random, or cluster sampling.

Question 2

Which of the following is an accurate statement about sample size?

Accepted Answer

Increasing the sample size usually leads to greater precision and accuracy in estimating population parameters, reducing sampling error and increasing statistical power. Therefore, a larger sample size is needed for increased accuracy. Choice A is incorrect because a smaller sample size tends to increase the size of the confidence interval due to increased variability and uncertainty. Choice B is also incorrect because sample size is not a constant percentage of population size, but depends on the research question, study design, sampling method, and desired level of precision. Choice D is incorrect because sample size is directly related to the confidence interval, as larger samples tend to produce narrower and more reliable confidence intervals.

Question 3

_____ indicates the amount of deviation in results obtained from a sample compared to the true population value.

Accepted Answer

Sampling error is the deviation in results obtained from a sample compared to the true population value. Syntax error refers to a mistake in the programming or coding of statistical software or analysis tools. Halo effect is a bias that occurs when a person's overall impression of someone or something affects their evaluation of specific traits or characteristics. Sample variance is a measure of the spread of data around the sample mean.

Question 4

A professor of mathematics wants to study how the students in his college perceive the subject.He walks into the college cafeteria and starts asking the students present there if they like mathematics.Which sampling technique is used by the professor in this scenario?

Accepted Answer

The professor is using haphazard sampling as he is simply asking the students who happen to be present in the cafeteria at that moment, without any specific plan or criteria. He is not targeting a specific subgroup of students or using any randomization procedure.

Question 5

Keziah stands outside a grocery store on the west side of the town and surveys exiting shoppers about their preference in frozen desserts.What type of sampling technique does Keziah's survey represent?

Accepted Answer

Keziah is using a nonprobability sampling technique because she is only surveying shoppers who happen to be exiting the grocery store on the west side of town, rather than randomly selecting from the entire population of the town.

Question 6

The city council wants to examine the citizens' opinions about allowing dogs at the city's beaches.It prepares a list of all the blocks in the city and randomly selects 20% of the blocks to sample.It then surveys all residents of the selected city blocks.Which of the following sampling techniques does this sampling strategy exemplify?

Accepted Answer

This sampling technique exemplifies cluster sampling because the city council selected a percentage of city blocks as clusters and surveyed all residents of those selected clusters.

Question 7

In which sampling technique do researchers choose a sample that reflects the numerical composition of various subgroups in a population?

Accepted Answer

Quota sampling is the technique in which researchers choose a sample that reflects the demographic composition of various subgroups in a population. This method ensures that the sample is representative of the different segments of the population, even if the selection is not completely random.

Question 8

With _____ sampling technique,each member of the population has an equal probability of being selected for the sample.

Accepted Answer

In simple random sampling, each member of the population has an equal chance of being selected for the sample, which makes it a fair and unbiased method of sampling. Haphazard sampling relies on choosing participants based on personal judgment and may not be representative of the population, cluster sampling involves dividing the population into clusters and selecting entire clusters at random which may not be representative of the population as a whole, and stratified random sampling selects participants based on certain characteristics, which may introduce bias into the sample.

Question 9

A researcher stands outside a restaurant and asks the youngsters leaving the restaurant if they enjoyed the food there.What type of sampling technique has the researcher employed?

Accepted Answer

The researcher has employed purposive sampling technique as they have purposefully selected a specific group of individuals (youngsters leaving the restaurant) to gather information about their experience with the food.

Question 10

Which of the following is a probability sampling technique?

Accepted Answer

Simple random sampling is a probability sampling technique where each member of the population has an equal chance of being selected for the sample. This method ensures that the sample is representative of the population and minimizes the potential for bias. Quota sampling, haphazard sampling, and purposive sampling are all non-probability sampling techniques.

Question 11

Angelika wants to study how sixth graders perform in math exams.She obtains a list of all districts in the state,randomly selects 5% of the districts,and administers achievement tests to all sixth graders in these districts.This sampling method used by Angelika is called _____ sampling.

Accepted Answer

The sampling method used by Angelika is cluster sampling because she selects a random sample of districts, rather than individual sixth graders, and administers the test to all sixth graders in those districts.

Question 12

Using a 95% confidence interval,Mike reports that 48% to 52% of the population favors Proposition D.The difference between 48% and 52% reflects the _____.

Accepted Answer

The difference between the lower and upper limit of the confidence interval reflects the sampling error, which is the amount of random variation that occurs due to the fact that only a subset of the population was surveyed. It is important to note that this sampling error could be reduced by increasing the sample size, but it can never be completely eliminated. The other options (census limits, confidence values, and sample size) are not relevant to the interpretation of a confidence interval.

Question 13

Which of the following best describes the relationship between sample size and confidence interval?

Accepted Answer

A larger sample size will reduce the size of the confidence interval. This is because as the sample size increases, the sample mean becomes a more accurate estimate of the population mean, resulting in less variability in the data and a narrower confidence interval.

Question 14

You read in the newspaper that Proposition Q is favored by 57% of those polled.The results of the survey are said to be accurate within ±2 percentage points using a 95% level of confidence.From the information provided,it can be inferred that the actual population value is probably between _____.

Accepted Answer

Since the poll indicates that Proposition Q is favored by 57% of those polled and the survey has an error margin of ±2 percentage points at the 95% level of confidence, we can construct a confidence interval for the population proportion p using the following formula:

Sample proportion ± Margin of error

where

Sample proportion = 0.57 
Margin of error = 0.02

Thus, the confidence interval can be written as:

0.57 ± 0.02

Simplifying, we get:

0.55 ≤ p ≤ 0.59

Therefore, we can infer that the actual population value of the proportion of people who favor Proposition Q is probably between 55% and 59%.

Thus, the correct answer is (C).

Question 15

Ricardo wants to study the academic performance of graduate students in the U.S.First,he decides that he will study schools in only 15 states and randomly selects those states.He then randomly selects 30 schools from these 15 states.Over a period of 3 months,Ricardo travels to these 30 schools and studies the academic performance of their students.Identify the sampling technique used by Ricardo in this scenario.

Accepted Answer

Ricardo used cluster sampling as he randomly selected 15 states and then randomly selected 30 schools from those states. By choosing schools in clusters, it reduces the cost and time that would have been spent traveling to individual schools across the country.

Question 16

_____ sampling has the advantage of a built-in assurance that the sample will accurately reflect the numerical composition of the various subgroups.

Accepted Answer

Stratified random sampling involves dividing the population into subgroups or strata and then randomly selecting a proportionate number of participants from each stratum. This ensures that each subgroup is represented in the sample in proportion to its size in the population, leading to greater accuracy in reflecting the numerical composition of the subgroups.

Question 17

Political analysts are interested in analyzing the social perceptions of the current Democratic Party candidates in New York City.The number of registered Democrats and Republicans in the city is known.To form a sample of 1000,the analysts send out a team to sample the Democrats and the Republicans in proportion to the numbers registered.The team goes to major shopping malls and stops people as they enter,asking whether they are registered with one of the two parties.If so,the person is asked to fill out a questionnaire.The sampling technique used here would best be described as:

Accepted Answer

The sampling technique used is stratified random sampling because the population (Democrats and Republicans) is first divided into strata based on party affiliation and then a random sample is drawn from each stratum in proportion to the size of the stratum.

Question 18

To assess the presidential candidate preferences of the registered voters in Maricopa county,classified by social class and age,a researcher randomly selects voters from each subgroup according to their proportion in the entire county.This sampling technique is called _____ sampling.

Accepted Answer

The sampling technique described involves dividing the population (registered voters in Maricopa county) into subgroups based on social class and age and selecting a random sample from each subgroup proportional to its size in the population. This is known as stratified random sampling. Quota sampling involves selecting a predetermined number of individuals from each subgroup, regardless of the subgroup's size in the population. Haphazard sampling involves selecting individuals without any specific criteria or structure. Simple random sampling involves randomly selecting individuals from the entire population without regard to subgroups. Therefore, the best choice is D - stratified random sampling.

Question 19

The head of the psychology department in a university is interested in finding the attitudes of her students toward implementing an internship as a requirement for completion of the degree.She obtains a list of all students who are psychology majors,randomly selects 100 students from the list,and surveys those who are selected.What type of sampling technique has she employed?

Accepted Answer

The head of the psychology department randomly selects 100 students from a list of all psychology majors. This represents simple random sampling, where each member of the population has the same chance of being selected.

Question 20

It is important to use _____ sampling when researchers want to make precise statements about a specific population on the basis of the results of their survey.

Accepted Answer

Probability sampling involves randomly selecting participants from a population, ensuring that each member of the population has an equal chance of being selected. This increases the likelihood that the sample is representative of the population, allowing for more accurate and generalizable conclusions to be drawn.

Quiz 7: Asking People About Themselves: Survey Research