Problem 6-19 Consider the following time series. 2 3 4 5 6 7 Y. 120 110 100 96 94 92 88 a. Choose the correct time series plot. (i) (ii) 140 140 120 120 100 100 80 80 Time Series Value Time Series Value 60 60 40 40 20 20 0 7 1 2 3 5 6 2 3 5 6 Time Period (t) Time Period (t) (iii) (iv) 140 140 120 120 100 100 80 80 Time Series Value Time Series Value 60 60 40 40 20 20 2 3 6 5 5 Time Period (t) Time Period (t)