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The linear regression results below are based on commercial properties that real estate agencies use to guide clients with quantitative information helpful to make rental decisions. A random sample of 26 properties are considered with data for the variables, age of the property (X1), operating expenses and taxes (X2), vacancy rates (X3), total square footage (X4), and rental rates (Y). Parameter Estimates Coefficients Standard Error Intercept 12.68946801 0.831594737 AGE(X1) -0.124934887 0.044376763 EXPENSE(X2) 0.243764408 0.094604055 VACRATE(X3) 1.49087511 1.337555539 SQFOOT(X4) 0.061196753 0.024873263 What is the upper limit of the 95% confidence interval estimate for the effect of a square footage increase on the mean rental rates of properties