Stats Final
In a simple linear regression problem, r and b1
must have the same sign
The least squares method minimizes one of the following?
SSE
What do we mean when we say that a simple linear regression model is "statistically" useful?
The model is a better predictor of Y than the sample mean, Y bar
If the correlation coefficient (r)=100, then
all the data points must fall exactly on a straight line with a positive slope
A measure of the degree of relatedness of two variables is
correlation
The difference between the actual y value and the predicted y value found using a regression equation is called the
residual
Testing for the existence of correlation is equivalent to
testing for the existence of the slope (B1)
Residuals represent
the difference between the actual y values and the predicted y values
An assumption of simple regression is
the error terms are independent
If a categorical independent variable contains 4 categories (levels), the number of dummy variable(s) needed to uniquely represent these categories is
3
The coefficient of determination must be
between 0 and +1
If the error variances in regression are not constant, the data are
heteroscedastic
What do you mean when we say that a simple linear regression model is "statistically" useful?
the model is a better predictor of Y than the sample Y bar
A dummy variable is used as an independent variable in a regression model when
the variable involved is categorical