Round all intermediate calculations to at least 4 decimal places.) Consider the following sample data, consisting of 20 observations. t yt t yt 1 12.1 11 13.5 2 12.2 12 9.8 3 9.3 13 9.6 4 12.8 14 14.5 5 8.6 15 14.9 6 9.3 16 12.4 7 14.3 17 11.2 8 12.1 18 8.8 9 11.5 19 11.8 10 15.1 20 10.0 Click here for the Excel Data File The data are plotted below. }]e}ru:td"teusdjlAbeLais,"uetr":e -1 test 132527060812513 a-2. Discuss the presence of random variations. The smoother appearance of the graph suggests the presence of random variations. The smoother appearance of the graph suggests the absence of random variations. The jagged appearance of the graph suggests the presence of random variations. The jagged appearance of the graph suggests the absence of random variations. b-1. Use the exponential smoothing method to make forecasts with = 0.2. (Round your answers to 2 decimal places.) t 1 yt 12.1 2 12.2 3 9.3 19 11.8 20 10.0 21 b-2. Compute the resulting MSE and MAD. (Do not round intermediate calculations. Round your answers to 2 decimal places.) MSE MAD c-1. Use the exponential smoothing method to make forecasts with = 0.4. (Round your answers to 2 decimal places.) t 1 yt 12.1 2 12.2 3 9.3 19 11.8 20 10.0 21 c-2. Compute the resulting MSE and MAD. (Do not round intermediate calculations. Round your answers to 2 decimal places.) MSE MAD d. Use the appropriate value of to make a forecast for period 21. (Round your answer to 2 decimal places.)