AP Statistics Flashcards: Selecting An Experimental Design

What this deck covers

This deck focuses on Selecting An Experimental Design, giving you a quick way to review the definitions, rules, and examples that matter most for AP Statistics.

How to use these flashcards

Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: What is an extraneous variable?

Answer: A variable not of interest but could affect the outcome. Must be controlled to avoid confounding the results.

Flashcard 2: Identify the role of random assignment in experimental design.

Answer: To ensure each participant has an equal chance of receiving any treatment. Creates comparable groups to isolate treatment effects.

Flashcard 3: In which design are subjects their own control?

Answer: Crossover design. Each subject receives all treatments as their control.

Flashcard 4: What is the main purpose of blinding in experiments?

Answer: To prevent bias in treatment administration and assessment. Eliminates placebo effects and experimenter bias.

Flashcard 5: In a randomized block design, what is the block?

Answer: A group of subjects that are similar in ways expected to affect the response. Homogeneous units within blocks reduce experimental error.

Flashcard 6: Which design is preferable for a small sample size?

Answer: Matched pairs design. Maximizes statistical power when subjects are limited.

Flashcard 7: What is the role of replication in a factorial design?

Answer: To assess the consistency of interaction effects. Multiple replications verify interaction effect reliability.

Flashcard 8: What is an independent variable in an experiment?

Answer: The variable that is manipulated by the researcher. The factor deliberately changed to test its effect.

Flashcard 9: What is an independent variable in an experiment?

Answer: The variable that is manipulated by the researcher. The factor deliberately changed to test its effect.

Flashcard 10: Which design is preferable for a small sample size?

Answer: Matched pairs design. Maximizes statistical power when subjects are limited.

Flashcard 11: What differentiates a quasi-experiment from a true experiment?

Answer: Lacks random assignment of subjects to treatments. Cannot randomly assign subjects to treatment conditions.

Flashcard 12: Choose the best design for testing interaction effects of multiple factors.

Answer: Factorial design. Can detect how factors combine to affect outcomes.

Flashcard 13: What is the primary reason for replication in experiments?

Answer: To increase reliability and accuracy of results. Multiple trials reduce impact of random variation.

Flashcard 14: Which method helps reduce sampling variability in experiments?

Answer: Replication. Multiple subjects per treatment reduce random variation effects.

Flashcard 15: In which design are subjects their own control?

Answer: Crossover design. Each subject receives all treatments as their control.

Flashcard 16: Define carryover effects in experimental design.

Answer: Effects of a previous treatment that influence outcomes in subsequent treatments. Previous treatments may affect responses to later treatments.

Flashcard 17: Identify the main advantage of a crossover design.

Answer: Each participant receives multiple treatments, reducing variability. Each subject serves as their own control group.

Flashcard 18: Which design is best for minimizing the impact of confounding variables?

Answer: Randomized controlled trial. Random assignment isolates treatment effects from confounders.

Flashcard 19: What is an advantage of a double-blind study?

Answer: Eliminates bias from both participants and researchers. Neither group knows treatment status, preventing bias.

Flashcard 20: Identify the key benefit of using a control group.

Answer: To isolate the effect of the independent variable. Shows changes due to treatment, not other factors.

Flashcard 21: What is the purpose of control groups in experiments?

Answer: To serve as a baseline for comparison to the treatment group. Establishes what happens without the experimental treatment.

Flashcard 22: What is the purpose of control groups in experiments?

Answer: To serve as a baseline for comparison to the treatment group. Establishes what happens without the experimental treatment.

Flashcard 23: In a randomized block design, what is the block?

Answer: A group of subjects that are similar in ways expected to affect the response. Homogeneous units within blocks reduce experimental error.

Flashcard 24: What is the Hawthorne effect?

Answer: Subjects change their behavior because they know they are being studied. Awareness of observation changes natural behavior patterns.

Flashcard 25: How does blocking improve experimental design?

Answer: Reduces variability by grouping similar experimental units. Grouping similar units decreases experimental error.

Flashcard 26: Choose the best design for testing interaction effects of multiple factors.

Answer: Factorial design. Can detect how factors combine to affect outcomes.

Flashcard 27: Identify the key benefit of using a control group.

Answer: To isolate the effect of the independent variable. Shows changes due to treatment, not other factors.

Flashcard 28: What is the main limitation of observational studies?

Answer: Cannot establish causation due to lack of control over variables. Missing manipulation prevents proving causation exists.

Flashcard 29: What is the role of replication in a factorial design?

Answer: To assess the consistency of interaction effects. Multiple replications verify interaction effect reliability.

Flashcard 30: In which scenario is a matched pairs design most useful?

Answer: When comparing two treatments with closely related subjects. Pairing controls for individual differences between subjects.

Flashcard 31: Identify the primary goal of randomization in experiments.

Answer: To eliminate bias and balance unknown factors. Random assignment distributes unknown confounders equally across groups.

Flashcard 32: What is the difference between a single-blind and double-blind study?

Answer: Single-blind: participants unaware of treatment. Double-blind: both participants and experimenters unaware. Prevents bias from expectations affecting results.

Flashcard 33: What is the difference between a single-blind and double-blind study?

Answer: Single-blind: participants unaware of treatment. Double-blind: both participants and experimenters unaware. Prevents bias from expectations affecting results.

Flashcard 34: Identify the primary goal of randomization in experiments.

Answer: To eliminate bias and balance unknown factors. Random assignment distributes unknown confounders equally across groups.

Flashcard 35: Identify the role of random assignment in experimental design.

Answer: To ensure each participant has an equal chance of receiving any treatment. Creates comparable groups to isolate treatment effects.

Flashcard 36: What is a matched pairs design?

Answer: A design where subjects are paired based on similarities and given different treatments. Reduces variability by controlling for subject characteristics.

Flashcard 37: Identify a key feature of a randomized controlled trial (RCT).

Answer: Subjects are randomly assigned to treatment and control groups. Gold standard design for establishing causal relationships.

Flashcard 38: What is a response variable?

Answer: The variable measured as the outcome of the experiment. The outcome measure affected by the independent variable.

Flashcard 39: What is a confounding variable?

Answer: A variable that influences both the dependent and independent variables, causing a false association. Creates spurious relationships between variables being studied.

Flashcard 40: What is an advantage of a double-blind study?

Answer: Eliminates bias from both participants and researchers. Neither group knows treatment status, preventing bias.

Flashcard 41: What is a placebo?

Answer: A substance with no therapeutic effect used as a control in testing new drugs. Controls for psychological effects of receiving treatment.

Flashcard 42: Define a block design in experiments.

Answer: Subjects are divided into blocks based on a characteristic, then randomized within blocks. Controls for known sources of variation before randomization.

Flashcard 43: Identify a key feature of a randomized controlled trial (RCT).

Answer: Subjects are randomly assigned to treatment and control groups. Gold standard design for establishing causal relationships.

Flashcard 44: What is the main purpose of blinding in experiments?

Answer: To prevent bias in treatment administration and assessment. Eliminates placebo effects and experimenter bias.

Flashcard 45: What is an observational study?

Answer: A study where researchers observe subjects without manipulating variables. Cannot establish causation, only associations between variables.

Flashcard 46: Identify one disadvantage of a completely randomized design.

Answer: Less effective if there is variability among experimental units. Cannot control for differences between experimental units.

Flashcard 47: How does blocking improve experimental design?

Answer: Reduces variability by grouping similar experimental units. Grouping similar units decreases experimental error.

Flashcard 48: Which design reduces variability due to known confounders?

Answer: Randomized block design. Blocking controls known sources of variation.

Flashcard 49: What differentiates a quasi-experiment from a true experiment?

Answer: Lacks random assignment of subjects to treatments. Cannot randomly assign subjects to treatment conditions.

Flashcard 50: Define carryover effects in experimental design.

Answer: Effects of a previous treatment that influence outcomes in subsequent treatments. Previous treatments may affect responses to later treatments.

Flashcard 51: What is an interaction effect?

Answer: When the effect of one factor depends on the level of another factor. Combined factor effects differ from individual effects.

Flashcard 52: What is a completely randomized design?

Answer: An experimental design where subjects are randomly assigned to treatments. Ensures each subject has equal probability of any treatment assignment.

Flashcard 53: What is the main challenge of a crossover design?

Answer: Potential carryover effects between treatments. Previous treatments may influence subsequent treatment responses.

Flashcard 54: What distinguishes an experiment from an observational study?

Answer: Experiments involve the manipulation of variables; observational studies do not. Only experiments can establish cause-and-effect relationships.

Flashcard 55: What is the primary purpose of a pilot study?

Answer: To test the feasibility and refine the study design. Identifies problems before conducting the full study.

Flashcard 56: Define a block design in experiments.

Answer: Subjects are divided into blocks based on a characteristic, then randomized within blocks. Controls for known sources of variation before randomization.

Flashcard 57: Which design is best for minimizing the impact of confounding variables?

Answer: Randomized controlled trial. Random assignment isolates treatment effects from confounders.

Flashcard 58: Identify the essential feature of a crossover design.

Answer: Participants receive all treatments in a sequence. Same subjects receive all treatments over time.

Flashcard 59: Which design reduces variability due to known confounders?

Answer: Randomized block design. Blocking controls known sources of variation.

Flashcard 60: Identify the essential feature of a crossover design.

Answer: Participants receive all treatments in a sequence. Same subjects receive all treatments over time.

Flashcard 61: What is an interaction effect?

Answer: When the effect of one factor depends on the level of another factor. Combined factor effects differ from individual effects.

Flashcard 62: Identify the main advantage of a crossover design.

Answer: Each participant receives multiple treatments, reducing variability. Each subject serves as their own control group.

Flashcard 63: What is an observational study?

Answer: A study where researchers observe subjects without manipulating variables. Cannot establish causation, only associations between variables.

Flashcard 64: Define a factorial design.

Answer: An experiment where two or more factors are tested simultaneously. Tests multiple factors and their interactions simultaneously.

Flashcard 65: What distinguishes an experiment from an observational study?

Answer: Experiments involve the manipulation of variables; observational studies do not. Only experiments can establish cause-and-effect relationships.

Flashcard 66: Identify one disadvantage of a completely randomized design.

Answer: Less effective if there is variability among experimental units. Cannot control for differences between experimental units.

Flashcard 67: Which method helps reduce sampling variability in experiments?

Answer: Replication. Multiple subjects per treatment reduce random variation effects.

Flashcard 68: What is the main limitation of observational studies?

Answer: Cannot establish causation due to lack of control over variables. Missing manipulation prevents proving causation exists.

Flashcard 69: What is the primary purpose of a pilot study?

Answer: To test the feasibility and refine the study design. Identifies problems before conducting the full study.

Flashcard 70: What is an extraneous variable?

Answer: A variable not of interest but could affect the outcome. Must be controlled to avoid confounding the results.

Flashcard 71: In which scenario is a matched pairs design most useful?

Answer: When comparing two treatments with closely related subjects. Pairing controls for individual differences between subjects.

Flashcard 72: What is the primary reason for replication in experiments?

Answer: To increase reliability and accuracy of results. Multiple trials reduce impact of random variation.

Flashcard 73: What is the main challenge of a crossover design?

Answer: Potential carryover effects between treatments. Previous treatments may influence subsequent treatment responses.

Flashcard 74: Define a factorial design.

Answer: An experiment where two or more factors are tested simultaneously. Tests multiple factors and their interactions simultaneously.