怎样算 NMSC Selection Index？

How to calculate Your NMSC Selection Index

NMSC uses a Selection Index based on PSAT/NMSQT scores as an initial screen of students who enter its scholarship programs.

To calculate your Selection Index, double the sum of your Reading, Writing and Language, and Math Test scores.

For example: if your testing score Reading: 23 (out of 38); Writing: 20 (out of 38); and Math: 26.5 (out of 38).  Your 

NMSC Selection Index= 2*(23+20+26.5)=139

例子：

PSAT的分如下

NMSC Selection Index= 2*(37+37+37.5)=223