Final answer:
The provided information relates to a linear regression model, and predictions can be made for sales growth by substituting the day into the linear equation given, not a polynomial model with degree 10.
Step-by-step explanation:
To fit a polynomial model with degree 10 and reduce the degree using backward elimination, one would typically start with a dataset and a high-degree polynomial model. However, backward elimination isn't mentioned in the data provided. Instead, provided details indicate a simple linear regression model for predicting sales growth, where the regression equation is given as îy = 101.32 + 2.48x. To predict sales on a given day, simply plug the value of the day into the x variable and calculate îy.
Prediction for Day 60
îy = 101.32 + 2.48(60) = 101.32 + 148.8 = 250.12 (thousands of dollars).
Prediction for Day 90
îy = 101.32 + 2.48(90) = 101.32 + 223.2 = 324.52 (thousands of dollars).