AP Psychology: Statistics

Ordinal Scale

Allows for rank order by which data can be sorted, but still does not allow for relative degree of difference between them

Interval Scale

Allows for the degree of difference between items, but not the ratio between them

Mean

Average; calculated by adding all the scores and then dividing that total by the number of scores

Alternate/Equivalent forms Reliability

Carrying out two different forms of the same test to the same individuals Measures consistency across different samples

Median

Central or middle number in a frequency distribution

Reliability

Consistency and accuracy of results

Biological-Evolutionary Perspective

Genes and hereditary aspects are the basis of this perspective

Inter-rater reliability

Gives a score of how much homogeneity or consensus the ratings have Measures scorer consistency

Bimodal

Having two modes

Positively Skewed Distribution

High scores are the outliers Test results in a difficult class

Norm-referenced test

Individuals scores compared to a normative sample Most psychologists tests

Criterion-referenced test

Interpreted in reference to a content objective, proficiency level or cut score

Intra-rater reliability

Is the degree of agreement among repeated administrations of a diagnostic test by a single rater Measures scorer consistency

Statistical Significance

Is the low probability of obtaining at least as extreme results given that the null hypothesis is true

Descriptive Statistics

Organize and summarize quantitative information about a group

Range

The highest score minus the lowest score

Validity

Whether or not results measure what they were intended to measure

Gambler's Fallacy

Wrongly assuming an occurrence is "due" to happen even when it is strictly a matter of chance Ex: gender of a baby

Ratio Scale

Numerical data with an absolute zero or absolute starting point Magnitude, equal intervals, and absolute zero

Frequency Histogram

Known as a bar graph

Frequency Polygon

Known as a line graph

Socio Cultural Perspective

Looks at how society makes an individual/ how the interaction between people and cultural relate

Negatively Skewed Distribution

Low scores are the outliers Test results in an easy class

Inferential Statistics

Make inferences and draw conclusions based on data Help psychologists decide whether they can generalize (apply) samples to the general population

Split Half Reliability

Measure of internal consistency where the test is split into two and the scores to each half of the test is compared with one another

Standard Deviation

Measure the amount of variation from the aberage

Criterion Validity

Measure the effectiveness of the test in comparison with performance on other similar assessments

Construct Validity

Measure the extent to which the label for what the test measures is accurate

Content Validity

Measure the extent to which the test adequately sample the content domain

Face Validity

Measures test takers perceptions concerning whether a test looks valid

Predictive Validity

Measures the effectiveness of the test

Mode

Most frequently occurring number

Nominal Scale

Numbers used solely for categorizing data into groups Ex: Political, Race, Jersey Number

Norms

Performance of a defined group on a given test Used to aid in the interpretation of a score by providing a relevant comparison

Percentile Score

Relative measure of performance that tells you where you scored in comparison to others

Test-Retest Reliability

Single person takes a test again under the same conditions Measures consistency across time

Cognitive Perspective

Study of how we interpret things/thinking and mental processes

Normal distribution

Symmetrical/ Bell Shaped Curve