In an experiment, the refractive index of water was found to be 1.35, 1.29, 1.32 and 1.36. What is the average refractive index of water?

In an experiment, the refractive index of water was found to be 1.35, 1.29, 1.32 and 1.36. What is the average refractive index of water?
एक प्रयोग में, पानी का अपवर्तनांक 1.35, 1.29, 1.32 और 1.36 पाया गया। पानी का औसत अपवर्तनांक ज्ञात कीजिए।