MCAT Chemical and Physical Foundations of Biological Systems Flashcards: Demonstrate Understanding Components Scientific Research

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This deck focuses on Demonstrate Understanding Components Scientific Research, giving you a quick way to review the definitions, rules, and examples that matter most for MCAT Chemical and Physical Foundations of Biological Systems.

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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: Identify the correct interpretation: Does correlation imply causation?

Answer: No; correlation does not establish causation. Associated variables may share a confounder or reverse causality, requiring experiments for proof.

Flashcard 2: Which study design manipulates an independent variable and measures its effect on a dependent variable?

Answer: Experiment. This design tests causality by altering one factor while controlling others to observe effects.

Flashcard 3: What is blinding (masking) primarily used to reduce in research studies?

Answer: Observer and participant expectancy effects. It prevents knowledge of treatment assignment from influencing observations or behaviors.

Flashcard 4: What is the typical decision rule when p < \alpha in null hypothesis significance testing?

Answer: Reject $H_0$. A low $p$-value indicates evidence against the null, warranting its dismissal at significance level $\alpha$.

Flashcard 5: Which change generally increases statistical power: increasing sample size or decreasing sample size?

Answer: Increasing sample size. Larger samples reduce variability, enhancing the ability to detect true effects.

Flashcard 6: What is the Hawthorne effect?

Answer: Behavior changes because participants know they are observed. Awareness of being studied can alter natural behavior, confounding results.

Flashcard 7: Which measure of central tendency is most sensitive to outliers: mean, median, or mode?

Answer: Mean. Extreme values disproportionately influence it as the arithmetic average.

Flashcard 8: What is a Type I error in hypothesis testing?

Answer: Rejecting a true $H_0$ (false positive). It occurs when evidence falsely suggests an effect, controlled by the significance level.

Flashcard 9: What is a confounding variable?

Answer: A third variable associated with both exposure and outcome. It distorts the perceived relationship between variables by influencing both independently.

Flashcard 10: What does the alternative hypothesis, $H_A$, state in hypothesis testing?

Answer: An effect or difference exists. It proposes the research claim of a significant effect or difference to challenge the null.

Flashcard 11: Which term describes a systematic error that shifts results away from the true value?

Answer: Bias. It introduces consistent deviation from accuracy due to flaws in study design or execution.

Flashcard 12: What is random assignment intended to minimize in an experimental study?

Answer: Selection bias and confounding. It ensures groups are comparable by evenly distributing potential confounders across conditions.

Flashcard 13: What is the purpose of a control group in an experiment?

Answer: Provides a baseline for comparison. It receives no treatment, allowing isolation of the experimental intervention's effect.

Flashcard 14: What is the key difference between random sampling and random assignment?

Answer: Sampling selects participants; assignment allocates groups. Random sampling draws from the population, while assignment randomizes participants into study groups.

Flashcard 15: Which measure of spread is defined as the square root of variance?

Answer: Standard deviation. It quantifies average deviation from the mean, derived from variance for interpretability.

Flashcard 16: What is a Type II error in hypothesis testing?

Answer: Failing to reject a false $H_0$ (false negative). It misses a real effect due to insufficient evidence, often from low power.

Flashcard 17: What is a placebo in the context of experimental research?

Answer: An inert treatment used as a control condition. It mimics active treatment without effects to control for psychological responses in trials.

Flashcard 18: What is statistical power in hypothesis testing?

Answer: Probability of rejecting a false $H_0$, equal to $1-\beta$. It measures a test's ability to detect true effects, reducing Type II error risk.

Flashcard 19: What is the independent variable in an experiment?

Answer: The variable the researcher manipulates. It is the factor deliberately changed to assess its impact on the outcome.

Flashcard 20: What is the dependent variable in an experiment?

Answer: The outcome variable that is measured. It reflects the effect of the independent variable and is observed for changes.

Flashcard 21: Which option best describes peer review in scientific research?

Answer: Independent expert evaluation before publication. It ensures quality and validity through scrutiny by field experts prior to dissemination.

Flashcard 22: What is the definition of a $p$-value?

Answer: Probability of results as extreme as observed if $H_0$ is true. It quantifies the likelihood of data under the null, guiding hypothesis rejection decisions.

Flashcard 23: What is the null hypothesis, $H_0$, in hypothesis testing?

Answer: No effect or no difference between groups. It assumes the default state of no relationship or effect to be tested against data.

Flashcard 24: What is the operational definition of a variable in scientific research?

Answer: A precise, measurable definition of the variable. It specifies how a concept is quantified to ensure consistency and replicability in studies.

Flashcard 25: What does a $95\%$ confidence interval for a mean represent in repeated sampling?

Answer: About $95\%$ of such intervals would contain the true mean. It estimates the range where the population parameter likely falls with 95% confidence across samples.