A Researcher Is Trying to Decide Whether or Not to Add

question 31

Essay

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:
​ $\widehat { y }$ = 23.62 + 18.86x₁ + 24.72x₂
​
SSE = 1,425 SSR = 1,326
​
He has also estimated the model with an additional variable x₃. The results are
​ $\widehat { y }$ = 25.32 + 15.29x₁ + 7.63x₂ + 12.72x₃
​
SSE = 1,300 SSR = 1,451
​
What advice would you give this researcher? Use a .05 level of significance.

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Definitions:

Label

A categorization or identification given to a data point or variable in research or data analysis.

Vertical Axis

The y-axis on a graph or chart, which is typically used to display the dependent variable in a data set.

Y-axis

The vertical axis in a graph or chart, typically used to represent the variable being measured or observed.

Graph

A visual representation of data designed to communicate information clearly and efficiently.