B. PA Research Methods and Statistics

Scale

set of numbers/symbols whose properties model empirical properties of the objects to which the numbers are assigned

Continuous Scale

exists when it is theoretically possible to divide any of the values of the scale variable

Discrete Scale

used to measure a discrete

Measurement

act of assigning numbers or symbols to characteristics of things according to rules

Rules

guidelines for representing the magnitude

Magnitude

Property of "moreness"

Equal Intervals

Difference between two points at any place on the scale has the same meaning as the difference between two other points that differ by the same number of scale units.

Absolute Zero

Obtained when nothing of the property being measured exists

Nominal

categorical data set; involve frequency tables (ex. IQ Classifications)

Ordinal

categorization w/ magnitude; involves ranking (ex. IQ Scores)

Interval

continuous data set; concept of equal intervals (ex. Statistical Analysis of IQ Scores)

Central Tendency

attempts to describe a whole set of data with a single value that represents the middle or center of its distribution

Mean

average score

Median

midpoint

Mode

most frequently occuring

Variability

attempts to describe a whole set of data based on how spread out the scores are in a distribution

Range

the difference between the lowest and highest score in a data set

Interquartile Range

the difference between the 3rd and 1st quartile

Semi

Interquartile Range

Standard Deviation

distance of the score from the mean

Location

attempts to describe a whole set of data based on its location in the distribution

Percentile

used to display position or rank

Percentage

means of comparing quantities

Quartile

the set of values which has three points dividing the data set into four identical parts

Decile

a quantile that groups the data into 10 equal frequencies

Skewness

degree of asymmetry observed in a probability distribution; imbalance in the distribution

Positively

Skewed

Negatively

Skewed

Kurtosis

a measure of the tailedness of a distribution; how often outliers occur

Leptokurtic

high peak

Mesokurtic

normal peak

Platykurtic

flat peak

Hypothesis Testing

educated guess that sets the direction of the research; initial response

Null Hypothesis $(H_{0})$

assumes there is no statistically significant relationship; default

Alternative Hypothesis $(H_{2})$

assumes there is a statistically significant relationship

Statistical Test

method of statistical inference used to decide whether the data sufficiently support a particular hypothesis; statistical treatment

Correlation

measure of the direction and strength of a relationship between 2 variables

Positive Correlation

as one variable increases, so does the other variable

Negative Correlation

as one variable increases, the other variable decreases

No Correlation

there is no relationship between the two variables

Coefficient of Determination $(r^{2})$

analyzes how the differences in 1 variable can be explained by a difference in a second variable

Coefficient of Alienation

proportion of variance in the dependent variable that is not accounted for by the independent variable

Bivariate Correlation

statistical tests that measure the association/connection between 2 variables

Prediction

statistical test that forecast future outcomes; cause and effect

Point

Biserial Correlation

Biserial Correlation

Special type of correlation that can measure causality

Logistic Regression

Classification method that estimates the probability of an event occurring

Multinomial Regression

Classification method that generalizes logistic regression to multiclass problems

Simple Linear Regression

Involves predicting the value of a dependent variable based on an independent variable

Multiple Regression

Involves predicting the value of a dependent variable based on $\ge2$ independent variables

Ordinal Regression

Used to predict behavior of ordinal level dependent variables with a set of independent variables

Chi

Squared Test

Paired Groups

measures 1 group with 2 data sets

Unpaired Groups

measures 2 different groups

T

Test

Independent T

test

Dependent T

test

Matched Groups

measures 1 group with $\ge3$ data sets

Unmatched Groups

measures $\ge3$ groups with different data sets

Analysis of Variance (ANOVA)

Checks if there are statistically significant difference between $\ge3$ groups

Repeated Measures ANOVA

tests whether there are statistically significant differences in $\ge3$ dependent samples

One

Way ANOVA

Two

Way ANOVA

Post Hoc Tests

tests used after an ANOVA to determine which groups are significantly different from each other

Tukey Post Hoc Test

Equal variances and sample size

Scheffe Post Hoc Test

Unequal sample size

Levene's Test

Checks whether several groups have the same variance in the population

Test for Homogeneity of Variances

Also called test of normality

Factor Analysis

used to test a theory / establish construct validity; generates factors to measure a domain

Common Factor Analysis

dimensionality reduction method that analyzes only the reliable common variance of data

Exploratory Analysis

initial test used to explore new constructs

Confirmatory Analysis

test used to revalidate / strengthen findings; rerun of the same data set

Principal Components Analysis

dimensionality reduction method that analyzes all the variance of data

Factor Loading

index that represents the ability of a factor to measure the domain / construct

Cross Loading

not accepted and must be removed (≥ 2 factors)

Pure Factor Loading

1 factor only; helps establish item validity

Scree Plots

Visual table that helps identify which factors should be retained

Elbow Method

retain where it first shifted

Kaiser Method

follows a cut

Test Development

an umbrella term for all that goes into the process of creating a test

Test Conceptualization

process of conceptualizing the construct, items included, and design of the test

Self

Report

Questionnaire

Easy to administer and score

Interview

Gathers rich, in

Interview

one

Open

Ended Questions

Closed

Ended Questions

Structured Interviews

method that relies on asking questions in a set order to collect data on a topic

Semi

Structured Interview

Unstructured Interview

none of the questions are predetermined

Focus Group

questions are presented to a group instead of one individual

Rank Order

Respondents are presented with several items simultaneously and asked to rank them in order of priority

Constant Sum

Respondents are asked to allocate a constant sum of units among a set of stimulus objects with respect to some criterion

Q

Sort Technique

Stapel Scale

Originally developed to measure the direction and intensity of an attitude simultaneously

Continuous Rating Scale

Respondents rate the objects by placing a mark at the appropriate position on a continuous line that runs from one extreme of the criterion variable to the other

Itemized Rating Scale

Respondents are required to select one of the limited numbers of categories that best describes an attribute being rated

Rating Scale

grouping of words, statements, or symbols on which judgments of the strength of a particular trait are indicated by the testtaker

Likert Scale

Respondents indicate their own attitudes by checking how strongly they agree or disagree with carefully worded statements that range from very positive to very negative towards the attitudinal object

Semantic Differential Scale

Seven