Methods and apparatus to evaluate model stability and fit

[0012] Market analysts may be given one or more tasks related to understanding the impact of different factors on sales over time. Market analysts may perform such work in response to client requests. These customers may be manufacturers, retailers, traders and / or wholesalers who wish to know and / or otherwise understand factors that help and / or hurt sales. Factors that can affect sales include, but are not limited to: promotional events (eg, TV promotions, radio promotions, print promotions, online promotions, etc.), macroeconomic factors and seasons.

[0013] To better understand what relationship exists between one or more factors, you can perform a statistical regression analysis using independent and dependent variables related to the customer's sales environment. Independent variables may include a variety of factors, some of which are under the client's control, such as, for example, promotional media type (eg, television, radio, etc.), promotional target audience, p