To calculate the absolute percent error for week 4, you can use the formula:
\[ \text{Absolute Percent Error} = \left| \frac{\text{Actual Value} - \text{Forecast}}{\text{Actual Value}} \right| \times 100% \]
For week 4, the actual value is 4 and the forecast is 8.00.
Plugging in the numbers:
\[ \text{Absolute Percent Error} = \left| \frac{4 - 8.00}{4} \right| \times 100% \]
Calculating the difference:
\[ 4 - 8.00 = -4 \]
Now plug that into the formula:
\[ \text{Absolute Percent Error} = \left| \frac{-4}{4} \right| \times 100% = \left| -1 \right| \times 100% = 1 \times 100% = 100% \]
Thus, the absolute percent error for week 4 is 100%.