HDFS 312 Exam 2

What is a population?

Everyone who belongs to a group of interest

In a perfect world, how would data be collected from a population?

By collecting data from everyone using a census

When does a census work best?

For small or known groups

What are challenges of studying large populations?

• Unknown total number of people

• Difficult to collect data from everyone

• Obstacles in data collection

• Data may be outdated by the time it’s analyzed

What are the benefits of a census?

Provides detailed information on:

• Rare or very specific populations

• Small geographic areas

What types of errors affect a census?

Non-sampling errors.

What are examples of non-sampling errors?

• Missing data (nonresponse)

• Misinterpretation of questions

Why might a population be hard to identify?

Some people may not want to share certain identities

What is a sample?

A subset of a population

Why are samples used?

To infer or understand the broader population

Why are samples used more often than censuses?

• Cheaper

• Quicker

• Easier to conduct

What is sampling?

The process of selecting a sample

What is the goal of sampling?

To create a sample that represents the broader population

Why are representative samples important?

They allow researchers to make accurate inferences about the population

How does participant selection affect results?

• Directly impacts validity (accuracy)

• Poor representation = inaccurate results

How does sampling indirectly affect results?

• Impacts significance and importance

• Too narrow = not generalizable

What is a representative sample?

A subset that reflects the population on key variables

Why is representativeness important?

It affects generalizability (applying results to the population)

What is an example of a representative sample?

Studying spending habits of the average American family

What is a homogeneous sample?

A sample where participants are similar in characteristics.

When are homogeneous samples useful?

• Reducing variability

• Isolating relationships between variables

• Increasing internal validity

Example of a homogeneous sample?

Adults aged 25–35 diagnosed with GAD in a CBT study

Why do homogeneous samples work?

• Same diagnosis and developmental stage

• Fewer confounding variables

What is a heterogeneous sample?

A very diverse sample

When are heterogeneous samples useful?

• Generalizability

• Studying group differences

• Validity across populations

Example of a heterogeneous sample?

Adults aged 18–85 studying technology use and well-being

Why do heterogeneous samples work?

• Age differences are central to the research question

• Allows comparisons across groups

What is probability sampling?

A method where every member of the population has an equal chance of being selected

Why is probability sampling considered the “gold standard”?

Because it produces more unbiased and representative samples.

What is non-probability sampling?

A method where not all individuals have an equal chance of being selected

What is a major issue with non-probability sampling?

It can produce biased samples and overrepresent certain groups

What are the advantages of probability sampling?

• Produces unbiased samples

• Good for broadly defined populations

What are the disadvantages of probability sampling?

• Difficult to execute

• Requires access to the full population

What are the advantages of non-probability sampling?

• Easier to conduct

• Useful for small or specialized populations

What are the disadvantages of non-probability sampling?

• Higher risk of bias

• Less generalizable results

What is simple random sampling?

Every individual has an equal chance of being selected

Give an example of simple random sampling

Drawing names out of a hat or pulling marbles randomly from a jar

Why is simple random sampling difficult to achieve?

It requires truly random methods to identify participants

What is systematic sampling?

Selecting every Nth person from a list or group

Why is systematic sampling considered semi-random?

Because the starting point may be random, but selection follows a fixed pattern

Give an example of systematic sampling.

Selecting every 3rd person in line

What is stratified random sampling?

Dividing a population into groups and randomly sampling from each group

What variables can be used to create strata?

Age, gender, race, occupation, etc.

Why use stratified sampling?

To ensure representation of important subgroups

What is cluster sampling?

Dividing a population into clusters and randomly sampling from those clusters

Give an example of cluster sampling

Using campuses as clusters when studying Penn State students

What is convenience sampling?

Selecting participants who are easiest to access

What is a drawback of convenience sampling?

It is usually not representative.

What is quota sampling?

Selecting participants to meet specific group quotas

How is quota sampling different from stratified sampling?

It is not random

What is purposive sampling?

Selecting participants based on specific characteristics

What is a key feature of purposive sampling?

The researcher intentionally chooses participants

What is snowball sampling?

Participants refer other participants.

When is snowball sampling useful?

For very small or hard-to-reach populations.

Drawing names out of a hat is what type of sampling?

Simple random sampling

Pulling pumpkins from the top of a bin is what type?

Convenience sampling

Selecting every 5th record after choosing a random bin is what type?

Systematic sampling

Choosing specific numbers of different apple types is what type?

Quota sampling

What is sampling error?

How closely a sample represents the population

What does a lower sampling error mean?

The sample is closer to reality

What is sampling bias?

The natural, unavoidable discrepancy between the sample mean and the true population mean

How can sampling bias occur?

• Excluding certain groups

• Overrepresenting others

How is science categorized based on outcome?

By whether it seeks knowledge or aims to fix a problem

What is basic research?

Research that seeks to understand something about the world

Give an example of basic research.

Studying the experiences of family caregivers

What is applied research?

Research that aims to solve a practical problem

Give an example of applied research.

Studying how class size affects student learning outcomes.

A community ceneter is facing a decline in attendance in youth programs and need to show community need for funding. What information does the center need?

• Program description

• Reasons for decline

• Location and time

• Funding source

• Community need

A community ceneter is facing a decline in attendance in youth programs and need to show community need for funding. Who should the center gather information from?

• Community leaders

• Program participants

• Program implementers

• Parents

What method answers: “What does the community need?”

Needs assessment.

What method answers: “Is our program working?”

Program evaluation

What method answers: “Who are we serving?”

Administrative data analysis

What method answers: “What do clients think?”

Surveys and interviews

What method answers: “Why are outcomes different?”

Mixed methods

What is a “need” in research terms?

The gap between what is provided and what is wanted

What is a needs assessment?

An evaluation used to identify gaps and community needs

What else does a needs assessment identify?

Community resources and assets.

What is the first step in a needs assessment?

Developing a plan

What is another term for community engaged scholarship?

Community-based participatory research.

When are community members involved in a community engaged scholarship?

From the very beginning.

How are community members involved in community engaged scholarship?

• Helping define problems

• Participating in data collection and analysis

What should researchers do after collecting results?

Share findings back with the community for implementation

What are key considerations in community engaged scholorship?

• Community guides the process

• Researchers must build trust

What is a program in this context?

An intervention designed to fix a problem

What are program objectives?

Goals that function like research questions

Why is program evaluation important?

It determines if the program works and supports funding decisions

What is formative evaluation?

Evaluation during program development to ensure it’s on the right track

What is summative evaluation?

Evaluation after the program is complete to see if it met its objectives

What are common methods used in program evaluation?

• Surveys (pre/post, knowledge checks)

• Interviews

• Expert panels

• Community-level data

Why are surveys commonly used in research?

• Relatively inexpensive

• Can reach large groups

• Collect a lot of data quickly

• Faster than interviews

What are some downsides of surveys?

• Questions can be nonspecific

• People may lie or give inaccurate answers

What is a survey?

A set of predetermined questions used to collect data

What are surveys useful for?

• Gathering general information about a population

• Guiding next steps for more in-depth research

Give an example of how surveys are used in practice

A director surveys clients about satisfaction and needs, then selects a smaller group for follow-up interviews

What is a questionnaire?

A list of questions (e.g., an intake form).

Why are surveys considered versatile?

They can be used for many different purposes with the same method

Give examples of survey purposes.

• Needs assessment → community priorities

• Satisfaction → client feedback

• Program outcomes → self-reported improvement

• Program improvement → staff climate survey

• Grant reporting → impact metrics

What are the main advantages of surveys?

• Quick data collection

• Cost-effective

• Can be generalizable (if sample is representative)

• Reliable and valid due to standardized questions

Why are surveys considered reliable?

Everyone is asked the same questions in the same way

What are key downsides of surveys?

• Inflexible once distributed

• Cannot adjust flawed questions

• May not fit all audiences (validity issues)