The air supply to the nozzle is to be maintained at a given total/stagnation pressure for the experiments to be run successfully. As seen in the schematic, air is supplied through a pressure regulator that controls the total pressure. A pressure transducer mounted on the nozzle plenum chamber (the straight section before the nozzle) is used to monitor the pressure in the chamber. The transducer has an accuracy of 0.5 psi and a resolution of 1 psi. Ten trials of pressurizing the plenum chamber to a total pressure of 25 psi are made to ascertain pressure controllability. The data yields a standard deviation in the total pressure to be 2 psi. Based on the data at hand, calculate the uncertainty in pressure controllability at 95% confidence level.