In order to obtain a confidence interval for the coefficient estimates, we can use the confint() command.

> confint(lm.fit)
                2.5 %     97.5 %
(Intercept) 33.448457 35.6592247
lstat       -1.026148 -0.8739505

By default R uses the 95% confidence level, the level parameter allows us to specify our own confidence level.

> confint(lm.fit, level = 0.95)
                2.5 %     97.5 %
(Intercept) 33.448457 35.6592247
lstat       -1.026148 -0.8739505

Try creating a 90% confidence interval for the model lm.fit:

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Assume that:

• The MASS library has been loaded
• The Boston dataset has been loaded and attached