7. A computer laboratory manager was interested in whether there was a difference in functioning time between three different branded battery packs for laptops. She took a random sample of six battery packs of each brand and tested them. The results, in hours of functioning before the need for a recharge, were recorded as follows:

As the manager was unsure whether the assumptions for the usual parametric analysis of variance were valid, she decided to employ nonparametric methods. Use the appropriate nonparametric procedure to determine whether the distribution of functioning time before needing a recharge is the same for the three brands of battery packs. Use α = 0.05.