[填空题]
The lifetime, in thousand j2gn ic1kvy3/ of hos:3al)vl m0vkurs, of LED bulbs at a manufacture plant were recorded for a periodic quality check. The data is illustrated in the boxv0 l3 ak):lsmv-and-whisker diagram shown below.
1. Write down the median lifetime of these LED bulbs. hours
2. Write down the upper quartile. hours
3. Find the interquartile range.
The lifetimes of these LED bulbs are normally distributed.
4. Find the longest lifetime of an LED bulb that is still not considered an outlier.
