please help me answer this problem

(10pts) A critical process output follows a normal distribution with mean equal to 437.6 cm and standard deviation equal to 2.5 cm. Engineering specifications are set at 435.0 + 4.5 cm This means that the lower specification limit is 430.5 cm and the upper specification limit is 439.5 cm.) What is the current yield of the process? After an improvement project, the process standard deviation has been reduced and now equals 2.0 cm. The mean and specifications remain the same as before. What is the resulting yield of the improved process