Finding standard error for elasticity (log-log model)

#1
Hi guys,

Can anyone help with this?

In(sub) = 3.43 - 0.899 In(Price) + 0.374 In(Age) + 0.141 In(Age)In(Price) + 0.229 In(Characters)

The standard error:
SE In(Price) = 0.145
SE In(Age) = 0.118
SE In(Age)In(Price) = 0.04
SE In(Characters) = 0.096

I need to find the elasticity which is the percentage change in y/percentage change in x.

I got (Percentage change in In(Subscription))/(Percentage change in In(Price))= -0.899+0.141 In Age

The age is given as 80 so I got the elasticity as -0.28

However, I'm not sure how to calculate the standard error. It was given in the book that SE = 0.06 but there's no steps provided.

Will really appreciate any help!