# Chapter 2

 The flashcards below were created by user aking13 on FreezingBlue Flashcards. Nominal Scales Qualitative system for categorizing objects or people i.e Female =1, Male = 2 Ordinal Scales Allows you to rank people or objects according to the quantity of a characteristic i.eClass Rank Interval Scales Allows ranking on a scale with equal units i.e IQs, GRE scores Ratio Scales Properties of interval scales with a true zero point ie height in inches, weight in pounds Distribution A set of scores Measures of Central Tendency 1) Mean2) Median3) Mode Measures of Variability 1) Range2) Variance3) Standard Deviation Variance Variance Measure of variability in distribution of scores Standard deviation Used in interpreting scores: square root of variance Correlation Coefficient mathematical measure of the relationship between two variables: range -1.0 to + 1.0sign indicates the patter of the relationshipsize indicates the strength of the relationship Scatterplots graph depicting the relationship between two variables. Each mark in the scatterplot actually represents two scores, an individual's scores on the X and Y variable Major Types of Correlations(4) 1) Pearson Product-Moment Correlation2) Spearman Rank-Difference Correlation3) Point-Biserial Correlation4) Biserial Correlation Pearson Product-Moment Correlation Both variables continuous and on an Interval or Ratio Scale Spearman Rank-Difference Correlation: both variables on an Ordinal Scale Point-Biserial Correlation ONe variable continuous and on Interval/Ratio scale, the other a genuine dichotomy Biserial Correlation Both variables continuous and on Interval/Ratio scale, but one is reduced o two categories Factors that effect correlations 1) If another type of relationship exists, traditional correlations may underestimate the correlation2) If there is a restriction of range in either variable, the magnitude of the correlation will be reduced Qualitative interpretation of correlations < .3 Weak.3 - .7 Moderate> .7 Strong Statistical Significance of Correlations determined both by the size of the correlation coefficient and the size of the sample Coefficient of Determiniation(r squared) The proportion of variance on one variable that is determined or predicatble from the other variable Coefficient of Nondetermination (1 - r squared) The proportion of variance in one variable that is not determined or predicatable from the other variable Linear Regression A statistical technique for predicting scores on one variable given a score on anotherPredicts criterion scores based on a perfect linear relationshipStrong correlations result in accurate predictions; weak correlations resul in less accurate predictions Authoraking13 ID36068 Card SetChapter 2 DescriptionChapter 2: The Basic Mathematics of Measurement Updated2010-09-20T21:01:49Z Show Answers