Exam 2 Flashcards
The less precise a measurement is, the lower association between:
that variable and any other variable
What can effect whether or not the strength of a relationship is underestimated?
Imprecision
A strong association may be found if a measure is:
Reliable and Fairly Precise
What must you consider when interpreting and applying the results of research into the association between variables?
Whether the sample studied truly represents the range of the population of interest
Generalization of results into practice is a judgment of the clinician, but the investigator must provide sufficient description
***What is the fundamental statistic for the analysis of interval and ratio data to estimate the strength of the association between variables?
Regression Analysis
***What is a special case of regression?
ANOVA
***What is the simplest form of regression?
Simple Linear
***What is used to measure the strength of the association between pairs of data that are interval or ratio?
Pearson r Value
***What can you use to estimate the association between multiple variables? And what test is better suited for this?
Multiple Regression; ANOVA
What is the value of a multiple regression test?
R2 Value
What does R2 measure?
The variance in the criterion variable (Y) explained by a predictor variable (X) or predictor variables
What is the difference between normal values for R and R2?
r: (-1 to 1)
R2: (0 to 1)
What value is indicative that the differences observed when studying a sample are reflective of true population differences?
P-Value
***What are the guidelines for interpreting r values?
Little, if any correlation: .00 to .25; 00 to -.25
Low Correlation: .26 to .49; -.26 to -.49
Moderate Correlation: .50 to .69; -.50 to -.69
High Correlation: .70 to .89; -.70 to .89
Very High Correlation: .90 to 1.0; -.90 to 1.0
What do Measures of Association not imply?
Cause and Effect
Although measures of association confirm cause and effect, these analyses can build useful what?
Predictive Models
What analysis method is used most often for Ordinal Data?
Spearman Rank Order Correlation “Spearman r” (e.g. Likert Scale)
What is the formula for a Spearman Rank Order Correlation?
r = 1 – ((6∑d2) / n(n2 – 1))
What is the most common approach for Nominal Data?
Cramer’s V Correlation “Chi Square”
What is one example of a Spearman r analysis?
Likert Scale
What is one example of a Chi Square analysis?
Testing the hypothesis that two nominal variables are independent
What can a Cramer’s V analysis identify?
A relationship, but it may have no suggestion of cause and effect
Are Spearman r and Cramer’s V parametric or nonparametric statistics?
Nonparametric
Are parametric or nonparametric statistics more powerful? Why?
Parametric, nonparametric uses less information in its calculation