A producer of picture frames uses a tracking signal with limits of 4 to decide whether a forecast should be reviewed. Given historical information for the past four weeks, compute the tracking signal and decide whether the forecast should be reviewed. The MAD for this item was computed as 2.

(For tracking signal: round your answers to 1 decimal place, e.g. 3.5.)

Weeks	Actual Sales	Forecast	Deviation	Cumulative Deviation	Tracking Signal
				6	3.0
1	10	11
2	12	13
3	12	13
4	10	14

The forecast should be reviewed in week select a week: 0 or 1 or 3 or 2 or 4