$1\mathrm{.}5$

points

Time Remaining $1$ hour $33$ minutes $3$ seconds$01$:$33$:$03$

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Time Remaining $1$ hour $33$ minutes $3$ seconds$01$:$33$:$03$

The accompanying data file contains $20$ observations for t and yt$.$

picture Click here for the Excel Data File

The data are plotted below.

a$.$ Discuss the presence of random variations.

multiple choice

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 $\backslash$alpha $=0\mathrm{.}2.($Do not round intermediate calculations and round final answers to $2$ decimal places.$)$

b$-2.$ Compute the resulting MSE and MAD. $($Do not round intermediate calculations and round final answers to $2$ decimal places.$)$

c$-1.$ Use the exponential smoothing method to make forecasts with $\backslash$alpha $=0\mathrm{.}4.($Do not round intermediate calculations and round final answers to $2$ decimal places.$)$

c$-2.$ Compute the resulting MSE and MAD. $($Do not round intermediate calculations and round final answers to $2$ decimal places.$)$