A small business hires a consultant to predict the increase in weekly sales of their product when advertising is increased to $750. Over the past the consultant finds that the average spend on advertising is $500 per week and the average weekly sales of the business is $10000. The consultant finds: " Using a simple linear regression I predict that sales will be $12500 if advertising is increased to $750. What is the estimated simple regression used by the consultant to make this prediction?