The following information on the seasonal-irregular component values is for a quarterly time series: $\begin{array}{l}
& \text { Seasonal-Irregular } \
\text { Quarter } & \text { Comp onent Values (StIt) } \
1&1.23,1.15,1.16 \
2&.86, .89, .83 \
3&.77, .72, .79 \
4&1.20,1.13,1.17
\end{array}$ The seasonal index for quarter 1 is ______.
A) .997
B) 1.18
C) 4
D) 3

Question

The following information on the seasonal-irregular component values is for a quarterly time series: $\begin{array}{l}
 & \text { Seasonal-Irregular } \
 \text { Quarter } & \text { Comp onent Values (StIt) } \
1&1.23,1.15,1.16 \
2&.86, .89, .83 \
3&.77, .72, .79 \
4&1.20,1.13,1.17
\end{array}$ The seasonal index for quarter 1 is ______.
A) .997
B) 1.18
C) 4
D) 3

Quizplus · Accepted Answer

To calculate the seasonal index for quarter 1, we need to divide the average Seasonal-Irregular Component value for quarter 1 by the overall average Seasonal-Irregular Component value across all quarters.

The average Seasonal-Irregular Component value for quarter 1 is (1.23 + 1.15 + 1.16)/3 = 1.18.

The overall average Seasonal-Irregular Component value across all quarters is (1.23 + 1.15 + 1.16 + 0.86 + 0.89 + 0.83 + 0.77 + 0.72 + 0.79 + 1.20 + 1.13 + 1.17)/12 = 1.00.

Therefore, the seasonal index for quarter 1 is 1.18/1.00 = 1.18.

Thus, the correct choice is B.

The Following Information on the Seasonal-Irregular Component Values Is for a Quarterly