0. Consider a random sample X1, X2, . . ., Xn from the shifted exponential pdf fðx; l; yÞ ¼ lelðxyÞ x y 0 otherwise Taking y ¼ 0 gives the pdf of the exponential distribution considered previously (with positive density to the right of zero). An example of the 360 CHAPTER 7 Point Estimation shifted exponential distribution appeared in Example 4.5, in which the variable of interest was time headway in traffic flow and y ¼ .5 was the minimum possible time headway. a. Obtain the maximum likelihood estimators of y and l. b. If n ¼ 10 time headway observations are made, resulting in the values 3.11, .64, 2.55, 2.20, 5.44, 3.42, 10.39, 8.93, 17.82, and 1.30, calculate the estimates of y and l.