Research methods
60 flashcards covering Research methods for the MCAT Chem / Phys / Psych / Soc section.
Research methods are the structured approaches scientists use to investigate questions and gather evidence, involving techniques like experiments, surveys, and data analysis. In fields such as chemistry, physics, psychology, and sociology, these methods help ensure results are reliable, objective, and reproducible, allowing researchers to test hypotheses, identify patterns, and draw meaningful conclusions about the world.
On the MCAT, research methods appear across sections, especially in Psych/Soc and Chem/Phys, through questions that test your ability to evaluate study designs, interpret data, and spot flaws in experiments. Common question types include identifying independent and dependent variables, understanding sampling biases, or analyzing statistical results; traps often involve mistaking correlation for causation or overlooking ethical issues. Focus on mastering concepts like control groups, validity, and hypothesis testing to tackle these effectively.
A concrete tip: Practice breaking down real studies to identify potential confounding variables.
Terms (60)
- 01
Independent variable
In an experiment, the variable that is deliberately changed or manipulated by the researcher to observe its effect on another variable.
- 02
Dependent variable
The variable that is measured or observed in an experiment to see how it responds to changes in the independent variable.
- 03
Control group
A group in an experiment that does not receive the treatment or manipulation, serving as a baseline for comparison with the experimental group.
- 04
Experimental group
The group in an experiment that receives the treatment or manipulation to test its effects compared to the control group.
- 05
Hypothesis
A testable prediction about the relationship between variables in a study, often derived from theory and guiding the research design.
- 06
Null hypothesis
A statement in statistical testing that assumes no effect or no difference between groups, which is tested to see if it can be rejected.
- 07
Alternative hypothesis
The hypothesis that posits an effect or difference between groups, accepted if the null hypothesis is rejected based on data.
- 08
Random assignment
The process of assigning participants to groups in an experiment by chance to minimize bias and ensure groups are comparable.
- 09
Random sampling
A method of selecting participants from a population where each individual has an equal chance of being chosen, aiming to make the sample representative.
- 10
Double-blind study
A research design where neither the participants nor the researchers know who is receiving the treatment, reducing bias in results.
- 11
Single-blind study
An experimental setup where participants are unaware of whether they are in the treatment or control group, but researchers know.
- 12
Placebo
An inactive substance or treatment given to control group participants to mimic the experimental condition, helping to isolate the treatment's true effects.
- 13
Confounding variable
An extraneous factor that correlates with both the independent and dependent variables, potentially distorting the interpretation of cause and effect.
- 14
Operational definition
A clear, precise description of how a variable will be measured or manipulated in a study, ensuring consistency and replicability.
- 15
Reliability
The extent to which a measurement tool produces consistent and stable results over time or across different conditions.
- 16
Validity
The degree to which a study or measurement accurately reflects the concept it is intended to measure, ensuring meaningful conclusions.
- 17
Internal validity
The confidence that the observed effects in a study are due to the manipulation of the independent variable and not other factors.
- 18
External validity
The extent to which the results of a study can be generalized to other populations, settings, or times beyond the specific research.
- 19
Correlation
A statistical measure of the strength and direction of the relationship between two variables, without implying causation.
- 20
Causation
A relationship where one variable directly influences another, established through controlled experiments rather than just correlation.
- 21
Mean
The average value of a dataset, calculated by summing all values and dividing by the number of values, used to summarize central tendency.
- 22
Median
The middle value in a dataset when ordered from least to greatest, providing a measure of central tendency that is less affected by outliers.
- 23
Mode
The most frequently occurring value in a dataset, indicating the peak of the distribution in measures of central tendency.
- 24
Standard deviation
A measure of the spread of data points around the mean, calculated as the square root of the variance, indicating data variability.
- 25
Variance
The average of the squared differences from the mean in a dataset, quantifying how much the data points deviate from the average.
- 26
P-value
The probability of obtaining results as extreme as observed, assuming the null hypothesis is true, used to determine statistical significance.
- 27
Statistical significance
A result that is unlikely to have occurred by chance, typically when the p-value is below a threshold like 0.05.
- 28
Confidence interval
A range of values likely to contain the true population parameter, based on sample data, often expressed with a confidence level like 95%.
- 29
Type I error
Rejecting the null hypothesis when it is actually true, representing a false positive in statistical testing.
- 30
Type II error
Failing to reject the null hypothesis when it is false, representing a false negative that can occur in hypothesis testing.
- 31
Sample size
The number of observations or participants in a study, which affects the precision and power of statistical analyses.
- 32
Population
The entire group of individuals or items that a study aims to draw conclusions about, from which a sample is selected.
- 33
Sampling error
The difference between a sample statistic and the true population parameter, arising from the random selection of the sample.
- 34
Bias in research
Systematic errors that skew results, such as selection bias or measurement bias, undermining the accuracy of findings.
- 35
Longitudinal study
A research design that follows the same subjects over an extended period to observe changes and developments over time.
- 36
Cross-sectional study
A study that collects data from a population at a single point in time, providing a snapshot of variables and their relationships.
- 37
Case study
An in-depth investigation of a single individual, group, or event, used to explore complex phenomena in real-world contexts.
- 38
Survey
A research method that gathers data from participants through questionnaires or interviews to assess opinions, behaviors, or characteristics.
- 39
Experiment
A controlled study where researchers manipulate an independent variable to observe its effect on a dependent variable, establishing causality.
- 40
Observational study
Research where variables are observed without manipulation, often used when experiments are unethical or impractical.
- 41
Quasi-experiment
A study similar to an experiment but without random assignment, often due to existing group differences, limiting causal inferences.
- 42
Meta-analysis
A statistical technique that combines results from multiple studies on the same topic to draw more robust conclusions.
- 43
Informed consent
The process of obtaining voluntary agreement from participants after fully informing them of the study's risks, benefits, and procedures.
- 44
IRB
An institutional review board that reviews and approves research involving human subjects to ensure ethical standards are met.
- 45
Debriefing
The post-study explanation provided to participants about the true nature and purpose of the research, especially if deception was used.
- 46
Confidentiality
The ethical obligation to protect participants' personal information from unauthorized disclosure during and after a study.
- 47
ANOVA
Analysis of variance, a statistical test used to compare means across three or more groups to determine if differences are significant.
- 48
T-test
A statistical test that compares the means of two groups to see if they are significantly different from each other.
- 49
Chi-square test
A statistical method used to test whether observed frequencies in categorical data differ significantly from expected frequencies.
- 50
Regression
A statistical analysis that models the relationship between a dependent variable and one or more independent variables to predict outcomes.
- 51
Scatterplot
A graph that displays the relationship between two continuous variables, with points representing data pairs to visualize correlations.
- 52
Bar graph
A chart that uses bars to compare the frequency or magnitude of categories, useful for displaying categorical data.
- 53
Line graph
A graph that plots data points connected by lines to show trends over time or continuous changes in variables.
- 54
Histogram
A graphical representation of the distribution of numerical data, using bars to show frequency within specified ranges.
- 55
Frequency distribution
A summary of how often each value or range of values occurs in a dataset, often displayed in tables or graphs.
- 56
Normal distribution
A symmetrical bell-shaped curve representing data where most values cluster around the mean, common in many natural phenomena.
- 57
Z-score
A standardized score that indicates how many standard deviations a data point is from the mean, used to compare values from different distributions.
- 58
Effect size
A quantitative measure of the magnitude of a phenomenon's effect, beyond just statistical significance, to assess practical importance.
- 59
Hawthorne effect
A phenomenon where individuals change their behavior because they know they are being observed, potentially biasing study results.
- 60
Placebo effect
The improvement in a participant's condition due to their belief in the treatment, even if the treatment is inactive.