Answer:
Nike's revenues in the first quarter increased by 16.8% relative to the fourth quarter.
Step-by-step explanation:
When assigning dummy variables, a number of dummies (the total number of variables less one) are always included.
In this case, Nike revenues are related to the dummies for each of the quarters in the year less 1. Base on this, the coefficient of 16.8 for the first quarter dummy indicates that the first quarter revenues for Nike increased by 16.8%, more than as compared to the fourth quarter revenues.
So, this quarterly dummies projects the coefficients which indicate the increase or decrease which was relative to the fourth quarter revenues. Base on this, the Nike's revenues in the first quarter increased by 16.8% relative to the fourth quarter.