Instruct: what is the average specific impulse for engines that have a SFC in lb/(lbf·h) of 7.95, and a Effective exhaust velocity (m/s) larger than 4,423
Output: SELECT AVG Specific impulse (s) FROM table WHERE SFC in lb/(lbf·h) = 7.95 AND Effective exhaust velocity (m/s) > 4,423