Chpt 12: Understanding Research Results: Description and Correlation (PSY302) Flashcards
(33 cards)
3 basic ways to discrete your results of a study of relationships with between variables:
Comparing group percents
Correlating scores of participants on 2 variables
Comparing each group means.
Def: Frequency Distribution
a set of scores typically from lowest to highest which indicates the number of times each score was obtained.
Def: Frequency polygons
uses a line to represent the frequencies of scores.
Def: Descriptive stats
precise statements of data taken from statistical math.
Def: Central tendency
a way to value the central score of each set.
Def: Variability
the amount of spread in a distribution of scores.
Def: Standard deviation
the average deviation of scores taken from the mean.
Def: Variance
the square of the SD
Def: range
Range: the diff between the highest score and the lowest.
_____ graphs are used when the values on the x axis are __________ categories.
Bar, nominal
_____ graphs are used when the values on the x axis are __________.
Line, numeric
Choosing the scale for a bar graph allows a common __________ that is sometimes used by scientists and often used by advertisers.
manipulation
Def: Correlation coefficient
a stat that describes how strongly variables are related to one another.
Def: Pearson product moment correlation coefficient
used when both variables have interval or ratio scale properties; called the Pearson r.
Provides info abt both the strength & the direction of the relationship.
Values can range from 0 to 1.00.
Results can be described visually using a scatter plot where each pair of scores is shown as a single point on a diagram.
If the range of possible value is __________, the magnitude of the correlation coefficient is _________.
restricted, reduced
Def: Restriction of range
an issue when scores on a variable are limited to a small subset of their possible values, making it more difficult to identify relationships for the variable to other variables of interest.
The Pearson product r is designed to detect only _____ relationships.
linear
If the relationship is curvilinear, the correlation coefficient will ____ indicate the existence of a relationship.
not
Def: Effect size
Effect size: the strength of association between variables.
The Pearson r correlation coefficient is one indicator of effect size; it indicates the strength of the linear association between 2 variables.
Small effects are near_______
Medium moderate effects are near ______
Large effects are above r = 50
Squared value of the coefficient r squared transforms the value of r to a ___________.
r=10, r = 30, percentage
Reporting effect size provides a scale of ______ that is __________ across all types of studies.
values, consistent
Def: Regression equations
Regression equations: calcs used to predict a person’s score on one variable when that person’s score on another variable is already known.
Y=a+bX where Y is the score we wish to predict, X is the score that is known, a is a constant, and b is the adjustment factor
To predict a future behavior (criterion variable) on the basis of one’s score on some other variable. It’s necessary to demonstrate that there is a reasonably _______ correlation between the 2.
high
Def: Multiple regression
Multiple regression: used to analyze the relationship between a criterion variable & more than one predictor variable.
