pressure sensor

i have a mpx2200a pressure sensor and would like to use it as a simple barometer. the pin out of the sensor is:

pin 1: gnd pin 2: vout+ pin 3: vin pin 4: vout-

can i use analogread for obtaining the voltage value returned at pin2 by connecting pin2 to analog pin0 and pin4 to gnd on the arduino. i have done this but don't seem to get the correct value.

well, i am pretty new at this and was going to use the sensor as a very simple barometer.

i would like to read the voltage coming from pin2 and use an equation to come up with the current barometric pressure. i guess i would need some sort of an op-amp to amplify the voltage huh?

what would i do with the vout- pin though, tie it to ground?

I'm imagining that the intent with this chip is to drive an instrumentation amp.

The Instrumentation amplifier's job is to take the 40 milli volt span between high and low pressure and make it meaningful. 0-40 milli volts is not a voltage that the arduino analog pin can make a lot of use out of.