Two chips are being considered for use in a certain system. The lifetime of chip 1 is modeled by a Gaussian random variable with mean 20, 000 hours and standard deviation 4000 hours (The probability of negative lifetime is negligible). The lifetime of chip2 is also a Gaussian random variable but with mean 22,000 hours and standard deviation 1000 hours. Which chip is preferred if the target lifetime of the system is 20.000 hours?