The file Cities contains a sample of 25 cities in the United States. Variables included are city average annual salary ($), unemployment rate (%), median home value ($thousands), number of violent crimes per 100,000 residents, average commuter travel time (minutes), and livability score, a rating on a scale of 0 to 100 that rates the overall livability of the city.

Source: Data extracted from “100 Best Places to Live in the USA,” available at bit.ly/2jYvtFz and “AARP Livability Index,” available at bit.ly/1Qbd6oj. 

Develop the most appropriate multiple regression model to predict average annual salary ($). Be sure to perform a thorough residual analysis and provide a detailed explanation of the results as part of your answer.