Statistics for the Behavioral Sciences Flashcards

These flashcards provide essential vocabulary and foundational definitions from the Privitera 'Statistics for the Behavioral Sciences' Fourth Edition, covering introductory concepts through advanced statistical tests.

Statistics

The analysis of observations and evaluation of scientific observations.

Descriptive Statistics

Statistical procedures used to summarize, organize, and make sense of observations and the presentation of data.

Inferential Statistics

Procedures used to draw conclusions about a population based on sample data.

Population

The entire set of individuals, items, or data points being studied.

Population Parameter

A characteristic or measure that describes an entire population.

Sample

A subset of individuals selected from a larger population.

Sample Statistic

A characteristic or value derived from a sample that is used to estimate a population parameter.

Experimental Method

A research method that demonstrates cause-and-effect by controlling conditions and manipulating variables.

Independent Variable

The variable that is manipulated by the researcher in an experiment.

Dependent Variable

The variable that is measured and expected to change as a result of the manipulation of the independent variable.

Quasi-Experimental Method

A research method used to test a hypothesis that lacks regular experimental controls, such as random assignment.

Correlational Method

A research design that measures the extent to which variables change together without researcher control over conditions.

Nominal Scale

A scale of measurement where numbers represent identity or categories with no quantitative value.

Ordinal Scale

A scale of measurement that conveys the rank or order of data points.

Interval Scale

An equidistant scale of measurement where differences are meaningful but there is no true zero.

Ratio Scale

A scale of measurement with equidistant units and a true zero, often considered ideal for behavioral science.

Continuous Variable

A variable that can take on an infinite number of values within a specific range.

Discrete Variable

A variable categorized by distinct, separate units or categories.

Outlier

A score that falls significantly above or below the other scores in a distribution.

Relative Frequency

The distribution of the proportion of scores, calculated as $\text{Relative Frequency} = \frac{\text{Observed frequency}}{\text{Total frequency count}}$.

Percentile Point

The raw score value below which a specific percentage of scores fall.

Percentile Rank

The percentage of scores in a distribution that fall below a specific raw score.

Histogram

A graphical display used to summarize continuous data by showing the frequency of scores in intervals.

Stem-and-Leaf Display

A graphical display listing all individual scores where the 'leaf' is the numbers right of a vertical line and the 'stem' is the numbers to the left.

Central Tendency

A statistical measure that identifies a single value as representative of an entire distribution.

Mean

The arithmetic average of a set of scores, calculated by summing all scores and dividing by the number of scores.

Median

The middle score in a distribution when the scores are listed in order; it is unaffected by outliers.

Mode

The most frequently occurring score in a distribution.

Variance

A measure of variability representing the average squared distance from the mean.

Standard Deviation

The square root of the variance, providing a measure of the average distance of scores from the mean.

Standard Error of the Mean

A measure of the sampling error, calculated as $\sigma_M = \frac{\sigma}{\sqrt{n}}$.

Type I Error

An incorrect decision made during hypothesis testing when the null hypothesis is rejected even though it is true in the population.

Type II Error

An incorrect decision made when the researcher fails to reject a null hypothesis that is actually false.

Cohen’s d

A measure of effect size that indicates the distance of an effect from zero in standard deviation units.

ANOVA (Analysis of Variance)

A statistical method used to compare the means of two or more independent groups or factors.

Main Effect

The effect of a single independent variable on the dependent variable, ignoring the effects of other variables.

Interaction

In a factorial design, this occurs when the effect of one factor depends on the level of another factor.

Correlation Coefficient (r)

A numerical value between $-1.00$ and $+1.00$ that describes the direction and strength of the relationship between two variables.

Linear Regression

A statistical procedure used to describe a linear relationship and predict the value of a criterion variable (Y) based on a predictor variable (X).

Chi-Square Test ($\chi^2$)

A nonparametric test used to analyze distances between observed and expected frequencies of categorical data.