A series of calibration tests is conducted on a pressure gage. At a known pressure of 1000 psia it is found that 30 percent of the readings are within 1 psia of the true value. At a known pressure of 500 psia, 40 percent of the readings are within 1 psia. At a pressure of 200 psia, 45 percent of the readings are within 1 psia. What conclusions do you draw from these readings? Can you estimate a standard deviation for the pressure gage?