A researcher is trying to decide whether or not to add another variable to his model.He has estimated the following model from a sample of 28 observations. 
He has also estimated the model with an additional variable X3.The results are 
What advice would you give this researcher? Use a .05 level of significance.
Definitions:
Regression Analysis
A statistical method used to understand the relationship between a dependent variable and one or more independent variables.
Statistical Technique
A method used in analyzing data that involves mathematical theories and formulas to uncover patterns, trends, and relationships within data sets.
Relationships
The way in which two or more concepts, objects, or people are connected, or the state of being connected.
Equal Level
A principle of maintaining the same rank or status among various elements or individuals.
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