Final answer:
The question about the catalytic converter does not correspond to known standards, but the related probability problem has an expected value of 8 days calculated using the formula for a uniformly distributed time interval.
Step-by-step explanation:
The original question about the length of time an independent garage must keep a failed catalytic converter does not correspond to any known regulation or standard practice, so it cannot be answered directly without additional context or clarification. However, it seems the question may be a confusion with another problem related to probability or expected value calculation regarding how long a parent can expect their child to clean their room, where the duration is uniformly distributed between one to fifteen days.
If we are dealing with the latter hypothetical scenario, the expected value (E) for a uniform distribution can be calculated using the formula E = (a + b) / 2, where 'a' and 'b' are the minimum and maximum values of the distribution. Thus, if the time it takes for children to clean their rooms is uniformly distributed from 1 to 15 days, the expected waiting time is (1 + 15) / 2 = 8 days.