Answer:
The answer is: The diffusion index of that group of manufacturing firms would be 0 (or remain the same if a previous diffusion index had been calculated)
Explanation:
A diffusion index is the common tendency within a group of numbers or statistics to either increase, decrease or remain the same.
The general formula for calculating the DI is:
Diffusion Index (DI) = (Increases−Decreases) + Previous DI Values
In this case, the diffusion index can be calculated by
Diffusion Index (DI) = (% orders increased - % orders decreased)
DI = 40% - 40% = 0