In a multiplicative model, if the seasonal factor is 1.15 for a particular season, then we expect that the time series in that season would be (other things being equal

15% above the trend.

Step-by-step explanation:

A time series represented by Y comprises of dataset observed over a particular period of time. Time series is handy in determining the future of a particular business.

In a multiplicative model, if the seasonal factor is 1.15 for a particular season, then we expect that the time series in that season would be

Y = T × C × S × 1

where;

Seasonal S = 1.15

As such Y would increase by 15% above the trend if all other things are being equal.

what is the original number? you forgot to add it.