Consider the following time series data.

Week 1 2 3 4 5 6

Value 19 13 17 12 18 13

Using the average of all the historical data as a forecast for the next period, compute the following measures of forecast accuracy. (Round your answers to two decimal places.)

(a)mean absolute error

MAE =

(b)mean squared error

MSE =

(c)mean absolute percentage error

MAPE =_________%

(d)What is the forecast for week 7?