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. 
SSE = 1,425
SSR = 1,326
He has also estimated the model with an additional variable X3. The results are 
SSE = 1,300
SSR = 1,451
What advice would you give this researcher? Use a .05 level of significance.
Definitions:
Observational Learning
Learning new behavior by watching a model perform that behavior.
Vicarious Learning
The process of learning behaviors by observing the actions of others and the outcomes of those actions, without directly experiencing it oneself.
Social Cognitive
Refers to the use of cognitive processes in relation to understanding the social world, emphasizing the role of observational learning, imitation, and modeling.
Psychodynamic
A theoretical approach in psychology that emphasizes the systematic study of the psychological forces that underlie human behavior, feelings, and emotions and how they might relate to early experience.
Q6: Refer to Exhibit 17-4. The price relative
Q8: Refer to Exhibit 14-8. The Y intercept
Q18: A regression model with one independent
Q31: Refer to Exhibit 16-4. The test statistic
Q33: Refer to Exhibit 21-4. The expected value
Q40: Aggregate price indexes reflecting the prices of
Q59: A multiple regression analysis between yearly
Q68: An ANOVA procedure is applied to data
Q77: It is believed that the median age
Q141: Refer to Exhibit 14-8. The coefficient of