PSYC331 – Statistics for Psychologists

These flashcards cover key concepts, definitions, and terminology related to the course 'Statistics for Psychologists', based on the lecture notes from PSYC331.

Statistics

A branch of mathematics that focuses on the organization, analysis, and interpretation of a group of numbers.

Descriptive Statistics

Used to summarize and describe quantitative information or data, providing an overall picture of the sample.

Inferential Statistics

Techniques that allow a researcher to draw inferences or conclusions about a population based on data obtained from a sample.

Variable

A characteristic that can take different values; variables can be continuous, discrete, or categorical.

Descriptive Statistics: Measures of Central Tendency

Includes mean, median, and mode which provide typical scores in a sample.

Mean

The sum of all scores in a sample divided by the number of scores.

Median

The middle score/value when all scores are ordered.

Mode

The most frequently occurring score in a dataset.

Variance

The average squared deviation of scores in a sample from the mean.

Standard Deviation

The square-root of the variance; it indicates the average variability of scores around their mean.

Normal Distribution

A probability distribution that is symmetric about the mean, depicting that data near the mean are more frequent in occurrence than data far from the mean.

Sample Statistic

Any estimate computed based on a sample.

Population Parameter

An estimate computed on a population.

Measurement Scales

Categorized into four types: nominal, ordinal, interval, and ratio based on their properties.

Nominal Scale

Classifies data into distinct categories without any inherent order.

Ordinal Scale

Classifies data into distinct categories with a natural order but does not indicate the degree of difference between categories.

Interval Scale

Measures data on a continuum with equal distances between points but lacks an absolute zero point.

Ratio Scale

The highest measurement scale that has all properties: identity, magnitude, equal intervals, and an absolute zero point.

Parametric Tests

Statistical tests used when the level of measurement is either ratio or interval.

Non-parametric Tests

Statistical tests used when the level of measurement is either ordinal or nominal.

Summation Notation (∑)

Represents the sum of a set of numbers.

Mean (Arithmetic Mean)

The sum of the numbers divided by the total number of observations.

Variance Formula

The population variance is calculated by summing the squared deviations from the mean divided by the number of observations.

Standard Deviation Calculation

The square root of the variance, providing a measure of variability in the same units as the original data.