2019年2月13日 星期三

What Regression Data Tables Commonly Tell Us

R Squared

  • The coefficient of determination. It tells you what percentage of the output variable is explained by the input variable. 
  • In other words, this tells you what percentage of the dependent variables that are entered around the mean are affected by the independent variables. If you got a 90 percent here, that means that 90 percent of the data is affected by the independent data.


Adjusted R Squared

  • This number is used if there is more than one regression model.
  • If you run a multiple regression test, with multiple independent variables all at the same time, then this number would be your test number.
  • It would act for each variable as the R squared would work for one variable.


Standard Error of the Regression

  • This measurement tells how much error was allowed for the overall test.
  • It measures the precision of the regression.
  • What you're testing for determining what level of error you're willing to accept.
  • If you are to use your regression as a first step in building a model, then you will need to pay very close attention to this number.
  • If you ran a regression of multiple variables and a few of them had a large error (meaning those variables tested with a very low precision level), then you would disregard these when building your model.


Sum of Squares (SS)

  • Regression mean square regression (MSR). This gives the regression sum of squares / regression degrees of freedom, whereas regression Mean Squares is defined as regression mean square error.
  • Significance F. This gives the significance level. Critical point for the F distribution is defined as F = MSR / MSE .

F distribution
  • An F statistic is a value you get when you run an Analysis of Variance (ANOVA) test of a regression analysis to find out if the means between two population are significantly different.
  • It's similar to a t from a t-test.
  • A t-test will tell you if a single variable is statistically significant, and an F test will tell you if a group of variables are jointly significant. 

(Source : "Statistics 101")