Quantitative Analysis Flashcards
Spurious Correlation
Used to refer to 1) correlation between two variables that reflects chance relationships in a particular data set, 2) correlation induced by a calculation that mixes each of two variables with a third, and 3) correlation between two variables arising not from a direct relation between them but from their relation to a third variable.
Linear Regression
Also known as linear least squares, computes a line that best fits the observations; it chooses values for intercept b0 and b1 that minimize the sum of the squared vertical distances between the observations and the regression line.
Standard Error of Estimate (SEE)
Measures uncertainty; is similar to the standard deviation for a single variable, except that it measures the standard deviation of the residual term in the regression. An indicator of the strength of the relationship between the dependent and independent variables. The SEE will be low if the relationship is strong and high if it is weak.
Coefficient of Determination (R^2)
The fraction of the total variation that is explained by the regression.
Type 1 Error
Rejecting the null when it is true.
Type 2 Error
Failing to reject the null when it is in fact false.
Analysis of Variance (ANOVA)
A statistical procedure for dividing the total variability into components that can be attributed to different sources. Used to determine usefulness of the independent variable or variables in explaining variation in the dependent variable.
Multiple R
Is the correlation of the two variables, which is also the square root of the R^2 for one variable equations.
Regression MSS
Explained Variation/degrees of freedom
Multiple Linear Regression
Allows you to determine the effect of more than one independent variable on a particular dependent variable.
Heteroskedastic
The variance of the errors differs across observations.
Unconditional Heteroskedasticity
Occurs when Heteroskedasticity of the error variance is not correlated with the independent variables in the multiple regression.
Conditional Heteroskedasticity
Heteroskedasticity in the error variance that is correlated with (conditional on) the values of the independent variables in the regression.
Serial Correlation
When regression errors are correlated across observations. Also known as, autocorrelated.
Positive Serial Correlation
Serial correlation in which a positive error for one observation increases the chance of a positive error for another observation. It also means that a negative error for one observation increases the chance of a negative error for another observation. The residual terms are correlated with one another, leading to coefficient error terms that are too small.