22 Matching Annotations
  1. Jun 2021
  2. Feb 2020
    1. assume that the average class in a district has 252525 students

      Assume that average student-to-teacher ratio in a district is 25 students. In regression model our dependent variable is student to teacher ratio not the size of the class. That's why, when we want to make a prediction we should take correct value for our explanatory variable.

      P.S. what is written would be correct if every class has one and only one teacher.

  3. Jul 2019
    1. In a simple linear regression model, we model the relationship between both variables by a straight line, formally

      It would be better to start in the following way: "To build simple linear regression model, we hypothesize that the relationship between dependent and independent variable is linear, formally:"

      By saying that, In a simple linear regression model, we model the relationship between both variables by straight line is strictly speaking wrong. Strictly speaking, by straight line we model the relationship between regressors the expected value of the dependent variable given the value of the regressors.

      Then later, you point out that the relationship is not exact because not all points fall on the straight line and because of that you come up with an error terms and you continue in this way util you arrive to the final formulation of the Simple Linear Regression Model. (Which you do well later).