Statistics for the Behavioral Sciences

What is statistics defined as?

The analysis and evaluation of scientific observations.

What are the two main branches of statistics?

Descriptive Statistics and Inferential Statistics.

What do descriptive statistics do?

They summarize and describe the characteristics of a specific data set.

What is datum?

A single measurement or observation.

What is data?

Multiple measurements or observations collected together.

What tools are used for presenting descriptive statistics?

Tables, graphs, and summary measures like the mean or standard deviation.

What is a population in research methodology?

The entire set of individuals, items, or data points of interest in a study.

What is a sample?

A subset of individuals selected from the population, intended to represent the larger group.

What is the purpose of randomization in experimental methods?

To give participants an equal chance of being assigned to any group and to control for preexisting differences.

What does the dependent variable represent in an experiment?

The variable that is measured and is hypothesized to be affected by the independent variable.

What is an operational definition?

A clear description of how a variable is measured or defined within a study.

What is a quasi-independent variable?

A variable that differentiates groups (like gender or age) that cannot be randomly assigned.

What does the correlational method measure?

The extent to which two variables change together.

What are the four characteristics of measurement scales?

Identity, order, difference, and ratio.

What is a nominal scale?

It represents an identity or category without any information about rank or quantity.

What is a continuous variable?

A variable that can take on an infinite number of values between any two points.

What is SPSS?

Statistical Package for the Social Sciences, a common tool for data analysis.

What is the purpose of frequency distributions?

To summarize data and compare scores by identifying the frequency of occurrences.

What is cumulative frequency?

The sum of frequencies at and below a particular interval.

What is a histogram?

A bar-style graph that represents frequency for continuous data.

What is the empirical rule in relation to standard deviation?

In a normal distribution, approximately 68% of scores fall within 1 SD, 95% within 2 SD, and 99.7% within 3 SD of the mean.

What is the null hypothesis in hypothesis testing?

A statement predicting no effect.

What is a Type I error?

Rejecting the null hypothesis when it is actually true.

What does Cohen’s d measure?

Effect size in terms of the number of standard deviations that mean scores shift above or below the population mean.

What is the purpose of the Chi-Square test?

To analyze categorical data to evaluate relationships between variables.

What is an assumption of Chi-Square tests regarding independence?

Each observation should be independent of others.

What is the expected frequency in a Chi-Square test?

The frequency that would be expected under the null hypothesis.

What is Cramer’s V used for?

To measure the strength of the association between two categorical variables.

What is indicated by a significant Chi-Square value?

That the observed frequencies differ significantly from the expected frequencies.

What is a limitation of Chi-Square tests?

Sensitivity to sample size; large samples may inflate test statistics.

What is the relationship between sample size and Type I error in ANOVA?

Using multiple t-tests increases the risk of Type I error, which ANOVA helps control.

What does the F-ratio in ANOVA represent?

The ratio of between-groups variation to within-groups variation.

What does a post hoc test do in ANOVA?

Determines which specific pairs of groups differ after finding a significant F value.

What does the Bonferroni procedure adjust?

Alpha levels for post hoc comparisons after ANOVA.

What is the definition of central tendency?

Measures that describe the center of a distribution.

What does the standard deviation measure?

The average distance of scores from the mean.

What is the Chi-Square Goodness-of-Fit Test?

Assesses how well observed frequencies align with expected frequencies.

What is the primary distinction of the Normal distribution?

It is symmetrical, unimodal, and mathematically defined by de Moivre.

What does the z-transformation accomplish?

Converts a raw score into standard units (number of standard deviations from the mean).

What does the Central Limit Theorem state?

The sampling distribution of the mean will be normal as sample size increases.

What is a two-way ANOVA used for?

To evaluate the interaction between two independent factors.