3- (a) In a least squares regression of J; on x, observations for which it is far from its mean will have more effect on the estimated slope than observations for which I is close to its mean value. Indicate whether the statement is true, false, or uncertain, and give a brief explanation. (13) Briey discuss the Brth and Pagan's test for \"heteroskedastieity\". (d) Discuss \"Dummy variable nap\" with an example