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Statistics - final
Final
24
Mathematics
Graduate
12/08/2012

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Term
Least Squares (OLS)- regression
Definition
sum of squares of the residuals
Term
correlation coefficient
Definition
r - calculated from a random sample of two variables.
measures goodness of fit about the linear least-squares regression line for the observed values of the dependent variable in the sample
Term
F-test (usage) in regression
Definition
tests the statistical significance of the entire regression
Term
WSS (ANOVA)
Definition
Unexplained variation of the residuals
Term
BSS (ANOva)
Definition
Explained variation
Term
Differences between bivariate and multivariate regression (2-variable and general linear model)
Definition
Adding 3rd or more variable
assumption of no perfect multicollinearity
Term
Residual Term in regression (ESS or BSS or SST)
Definition
ESS or BSS - difference btw mean Y and predicted Y - explained.

(treatment variation, explained sum of squares, variation between samples, the variation due to Factor A)
Term
RSS or WSS or SSE
Definition
difference between Y and predicted Y - unexplained but accounted for
(random variation, residual sum of squares, the variation within samples, the error variation)
Term
TSS
Definition
BSS+WSS - sum of squares of the residuals with respect to the mean
Term
u-hat
Definition
unexplained and unaccounted for either because of the lack of inclusion of a variable (violation) or inadequacy of the sample
Term
Why use variances in ANOVA
Definition
Allows the test of the null hypothesis that of the relationship between the datasets when sets are not the same type: eg ordinal to interval, categorical to ratio, ordinal to ratio, categorical to interval
Term
Concept of the standard error of the regression
Definition
The average error in predicting Y
Term
Anova (null hypothesis)
Definition
H0: mu1=mu2...mux (x=number of categories - BSS)
H0: mu1=mu2...mux (x=number of rows - WSS)
Term
ANOVA assumptions
Definition
1. Populations normally distributed
2. Samples are independent
3. The variances of the populations must be equal
4. The groups must have the same sample size
Term
General Linear (multivariate) regression assumptions
Definition
1. Non-autocorrelation (non-serial correlation or non-autoregression)
2. Homoscedascticity
3. Zero means
4. Nonstochastic
5. Correct specifications
6. Stochastic error term
7. No perfect multicollinearity
Term
Non-autocorrelation
Definition
Error termes do not have a relationship with each other. Knowing one does not allow prediction of another
Term
Homoscedasticity
Definition
variance is constant and random effects are throughout the data set. Var (ui) = E(ui2) = σ2
Term
Zero means
Definition
normal distribution: error terms normally distributed around the regression line?? Will cancel each other out [E(ui) = 0]
Term
Nonstochastic
Definition
error terms are not related to independent variables
Term
Correct specification
Definition
Y = B1 + B2Xi + ui or Y-hat = B1 + B2Xi – correct variables and formula, include all relevant variables (no violating assumptions or leaving relevant variables out)
Term
no perfect multicollinearity
Definition
independent variables are independent
Term
Why ANOVA
Definition
tests differences between two or more population means. An extension of a t-test
Term
BLUE
Definition
Best Linear Unbiased Estimate
1. Accuracy (Efficiency) - the variance of the sampling distribution of beta-hats will be the minimum for any estmators of beta
2. Beta-hat fits on beta
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