Thanks!

But if the range is from 17 to 308 kPa and 0.25V to 4.75V, the linear range would be (308-17)/(4.75-4.25) = 64.67 kPa/V

I don't know where you got your linear value from?

Edited: Ah, I see. Your linear rate should be 0.01546 V/kPa.