Step-by-Step Guidance for Descriptive Statistics Exam Study

Study Guide - Smart Notes

Tailored notes based on your materials, expanded with key definitions, examples, and context.

Q1. Bob is interested in how much community college students work outside of school. Bob decides to ask the students in his psychology class, including himself, the question: "How many hours did you work in the last two weeks?" and records the value.

Background

Topic: Sampling Methods & Types of Data

This question tests your understanding of how samples are collected and the difference between population, sample, and study group.

Key Terms:

Population: The entire group Bob wants to learn about (all community college students).
Sample: The subset of the population that Bob actually surveys (students in his psychology class).
Study Group: The group being directly observed or measured.

Step-by-Step Guidance

Identify what Bob is collecting: Is it data from the population, a sample, or just his class?
Consider whether the students in Bob's psychology class represent all community college students.
Think about the implications of including himself in the data.
Reflect on whether this is a random sample or a convenience sample.

Try solving on your own before revealing the answer!

Final Answer:

Bob is collecting a convenience sample from his psychology class, not the entire population of community college students.

This sample may not be representative of all community college students, so results may be biased.

Q2. In the study, community college students are the ______.

Background

Topic: Identifying Populations in Research

This question tests your ability to distinguish between the population and the sample in a study.

Key Terms:

Population: The group the researcher wants to generalize about.
Sample: The group actually surveyed.

Step-by-Step Guidance

Recall the definition of population in statistics.
Identify who Bob wants to learn about (all community college students).
Compare this to the group he actually surveys.

Try solving on your own before revealing the answer!

Final Answer:

Community college students are the population in this study.

Bob's sample is the students in his psychology class.

Q3. In the study, Bob's psychology class is the ______.

Background

Topic: Identifying Samples in Research

This question tests your understanding of what constitutes a sample in a research study.

Key Terms:

Sample: The group actually surveyed or measured.

Step-by-Step Guidance

Recall the definition of sample.
Identify the group Bob actually collects data from.
Compare this to the population.

Try solving on your own before revealing the answer!

Final Answer:

Bob's psychology class is the sample in this study.

The sample is the subset of the population that is actually surveyed.

Q4. Bob is studying (a) ______.

Background

Topic: Identifying Variables in Research

This question tests your ability to identify the variable being studied.

Key Terms:

Variable: The characteristic or property being measured (e.g., hours worked).

Step-by-Step Guidance

Identify what Bob is measuring or recording.
Think about the question Bob asks his class.
Determine the variable of interest.

Try solving on your own before revealing the answer!

Final Answer:

Bob is studying the variable "hours worked in the last two weeks".

This is the characteristic being measured in the sample.

Q5. Justify your answer for #5: How do you know?

Background

Topic: Justifying Variable Identification

This question tests your ability to explain your reasoning for identifying the variable.

Key Terms:

Justification: Providing evidence or reasoning for your answer.

Step-by-Step Guidance

Restate what Bob is measuring.
Explain why this is considered a variable in statistics.
Connect your reasoning to the definition of variable.

Try solving on your own before revealing the answer!

Final Answer:

The variable is "hours worked" because it is the characteristic being measured and can vary among students.

Variables are properties that can take on different values for different individuals.

Q6. Ella wants to know if plants will grow faster if they listen to Taylor Swift music. She harvests seeds from the same plant and puts them in two pots with the same soil. Both pots are placed in the same location and watered equally. In one pot, plants listen to music. She then measures the height of each plant over the course of a month.

Background

Topic: Experimental Design & Variables

This question tests your understanding of independent and dependent variables, and control in experiments.

Key Terms:

Independent Variable: The factor manipulated (music exposure).
Dependent Variable: The outcome measured (plant height).
Control: Keeping other factors constant.

Step-by-Step Guidance

Identify what Ella is changing in the experiment (music exposure).
Identify what Ella is measuring (plant height).
Consider what variables are controlled (soil, water, location).
Think about how the experiment is designed to test the effect of music.

Try solving on your own before revealing the answer!

Final Answer:

The independent variable is music exposure; the dependent variable is plant height.

Ella is using a controlled experiment to test the effect of music on plant growth.

Q7. Music would be the ______ variable.

Background

Topic: Identifying Independent Variables

This question tests your ability to identify the independent variable in an experiment.

Key Terms:

Independent Variable: The factor that is intentionally changed or manipulated.

Step-by-Step Guidance

Recall the definition of independent variable.
Identify what Ella is manipulating in the experiment.
Connect this to the role of the independent variable.

Try solving on your own before revealing the answer!

Final Answer:

Music is the independent variable in Ella's experiment.

It is the factor she intentionally changes to observe its effect on plant growth.

Q8. Plant height would be the ______ variable.

Background

Topic: Identifying Dependent Variables

This question tests your ability to identify the dependent variable in an experiment.

Key Terms:

Dependent Variable: The outcome measured in response to changes in the independent variable.

Step-by-Step Guidance

Recall the definition of dependent variable.
Identify what Ella is measuring as the outcome.
Connect this to the role of the dependent variable.

Try solving on your own before revealing the answer!

Final Answer:

Plant height is the dependent variable in Ella's experiment.

It is the outcome measured to see if music affects growth.

Q9. Ella is using a ______.

Background

Topic: Types of Studies

This question tests your ability to distinguish between experimental and observational studies.

Key Terms:

Experiment: A study where the researcher manipulates variables.
Observational Study: A study where the researcher observes without intervention.

Step-by-Step Guidance

Recall the difference between experiment and observational study.
Identify whether Ella is manipulating any variables.
Connect this to the definition of experiment.

Try solving on your own before revealing the answer!

Final Answer:

Ella is using an experiment because she manipulates the music variable to test its effect on plant growth.

Q10. Justify your answer for #9: How do you know?

Background

Topic: Justifying Study Type Identification

This question tests your ability to explain your reasoning for identifying the type of study.

Key Terms:

Justification: Providing evidence or reasoning for your answer.

Step-by-Step Guidance

Restate what Ella is doing in the experiment.
Explain why this is considered an experiment.
Connect your reasoning to the definition of experiment.

Try solving on your own before revealing the answer!

Final Answer:

Ella is conducting an experiment because she intentionally manipulates the music variable and measures its effect on plant height.