How to calculate Mean Coefficient of Linear Thermal Expansion Between 70°F and Indicated Temperature?

Because i need enter in material table for a specific material?

There should be no need to calculate a Mean Coefficient of Thermal Expansion because you usually only care about the coefficient's value at your operating/design temperature. Each temperature has its own coefficient value that can be used to calculate exact thermal growth AT that specific temperature.

If you have a temperature value that lies in between two table values (say you want it as 130°F) then it's as easy as doing linear interpolation.

You can either refer to the engineering codes (ASME) for the tables, or I've sometimes gone to the CAESAR Material Database and pull the values from there.