Term

Definition
include the important predictors in your model without attempting to add every explanation 


Term

Definition
the simplest explanation is usually the best one 


Term

Definition
those in which the coding of the variable is a close reflection of their meaning 


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Definition
(interval) can assume any real value, i.e. temperature 


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Definition
(count data) can only assume integer values, cannot be divided into fractions, i.e. number of children 


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Definition
those whose numerical representation in the data set simply classifies mutually exclusive values of the variable, but those numerical representations are substantially less meaningful than what is found with quantitative variables 


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Definition
qualitative variables in which the numbers represent a hierarchy of values. i.e., attitudes or grade in school 


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Definition
qualitative variables in which the numeric values assigned to values are merely placeholders, i.e. race 


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Definition
(binary variables) variables in which there are two and only two possible outcomes 


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Definition
binary variables that have been coded with 0 and 1 


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Definition
new variable created by adding up a number of variables together 


Term

Definition
new variable created by combining (sometimes weighting) variables to create something new altogether, i.e. socioeconomic status 


Term

Definition
underlying construct of the components in a scale 


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Definition
indirectly measured construct, i.e. socioeconomic status 


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Definition
a condition created when two or more variables measure the same underlying construct 


Term

Definition
refers to any one of a number of mathematical techniques for transforming variables so that they are in a single metric 


Term

Definition
2 or more variables are measuring the same thing (score on one variable should predict the score on another variable0 


Term

Definition
measures the internal consistency of several variables. Alpha reliability ranges from 0 to 1, where 1 is perfect internal reliability and 0 is the variables do not measure the same thing at all. (alphas greater than .7 are generally considered to have enough internal relaibility that scaling is warranted 


Term
exploratory factor analysis (purpose) 

Definition
1) can be used to see if a single variable can be used to replace multiple variables 2) can determine if several variables can be scaled together 3) detect clusters of variables 


Term
3 types of factor analysis 

Definition
1) Exploratory factor analysis (EFA) 2) Principal component analysis (PCA) 3) Confirmatory factor analysis (CFA) 


Term
Pearson's correlation coefficient 

Definition
used to understand how variables are related to each other; measured from 1 to 1 (negative number=negative association; positive number=positive association) 


Term

Definition
produced by EFA; measures the combination of the linear composites and the structure coefficients 


Term

Definition
in a factor matrix, the amount of weight you would give a variable if you were going to put it in a scale 


Term
3 stages of factor analysis 

Definition
1) Selection 2) Extraction 3) Rotation 


Term
Selection stage of factor analysis 

Definition
determine the number of factors that are meaningfully represented by the variables 


Term

Definition
in factor analysis, indicates the variance accounted for by each underlying factor 


Term

Definition
in selection of FA, the total number of factors represented by a set of variables is equal to the number of eigenvalues greater than 1 


Term

Definition
in selection stage of FA, a graph with the factors on the x axis and the eigenvalues on the yaxis. The scree that occurs after the curve bends is simply error variation and does not represent true factors 


Term

Definition
2nd stage of FA, the process by which we account for variance 


Term
best method for FA extraction 

Definition
principal axis factoring with iterated communalities (least squares) best approach, especially if smaller sample size 


Term

Definition
3rd stage of FA, extremely complex mathematical procedure that requires you to think in crazy dimensions. Basically, it rotates the axis to place it nearer to the data points 


Term

Definition
Type of rotation in FA; assumes factors are uncorrelated to each other 


Term

Definition
type of rotation in FA; assumes correaltion 


Term
Rule of thumb when determining which variables load on which factors in FA 

Definition
1) factor should have at least 4 variables 2) each variable should load close to or higher than +/ .5 


Term

Definition
a measure of whether the data are peaked or flat relative to normal distribution 


Term

Definition
mean and standard deviation 


Term

Definition
show bivariate differences of means or proportions 


Term
which inferential statistics to use if 1)using percents or proportions 2)means 

Definition
1) Pearson's ChiSquare 2)Student's ttest or an ftest derived from ANOVA 


Term

Definition
how most nominal and ordinal data are entered into models; a dummy variable is created for each category of the variable 


Term

Definition
used to compare 2 (and ONLY 2) means to see if they are statistically different from each other. Most often use the twotailed ttest where Ho= means are equivalent and Ha= means are different. First, must test for equal variance. p< .05 means we are 95% sure that the difference in means observed is not simply due to sampling error. 


Term
Robust test for equal variance 

Definition
used before a ttest can be conducted to determine whether the two groups have equal variance on the variable under question. Want p > .05 


Term
Levene's test for equal variance 

Definition
most common used robust test for equality of variance; (w0) ONLY indicates whether you have equal variance, not if you have statistically significant differences of means. Ho= equal variance; ha= unequal varaince. want p> .05 


Term

Definition
(Analysis of variance ftest): used when comparing the means of three or more groups. Oneway ANOVA ho= all means are equal; Ha= at least two groups have different means. If p is significant, then must conduct a posthoc test 


Term
3 types of posthoc tests 

Definition
Used after geting a significant p value in a oneway ANOVA. 1) Bonferroni 2) Scheffe 3) Sidak 


Term
Barlett's test for equal variance 

Definition
Addresses the major limiting assumption of ANOVA which assumes that the population variances are equal. Ho= equal varainces, Ha= unequal variances. Pant p > .05 so we fail to reject the Ho 


Term

Definition
a statistical technique used to measure and describe a relationship between two continuous variables. 

