Suppose as part of your job you are responsible for installing emergency lighting in a series of state office buildings. Bids have been received from four manufacturers of battery-operated emergency lights. The costs are about equal, so the decision will be based on the length of time the lights last before failing.
A sample of four lights from each manufacturer has been tested, with the following values (time in hours) recorded for each manufacturer:

Using α = 0.01, what conclusion for the four manufacturers should you reach about the median length of time the lights last before failing? Explain.