Definition of Marketing Mix
Marketing mix is the combination of marketing activities used to generate customers.  If you’re like most companies, your marketing mix consists of many activities. Certain marketing activities affect acquisition and others affect retention, all of which influence customer lifetime value and customer equity (all customers’ lifetime value combined).   

Other external factors such as interest rates, housing starts and weather may affect customer equity as well.  And other controllable factors such as the number of sales people or the number of retail units are also drivers. 

Definition of Econometrics

Econometrics analyzes all this data across time and determines which drivers are the most and least effective on the outcome, which in this example is customer equity.  An outcome can also be profits or market share, for example.