Question 9 of 15 (1 point) | Attempt 1 of 1 | @ 2h 55m Remaining 6.2 Section Exercise 24 Ages of Passenger Cars The average age of passenger train cars is 19.4 years. If the distribution of ages is normal and 25% of olo the cars are older than 23.2 years, find the standard deviation. Round z-value calculations to 2 decimal places and final answer to 2 decimal places. The standard deviation must be years