Wear-out of used display panels. Wear-out failure time of electronic components is often a...

Wear-out of used display panels. Wear-out failure time of electronic components is often assumed to have a normal distribution. Can the normal distribution be applied to the wear-out of used manufactured products, such as colored display panels? A lot of 50 used display panels was purchased by an outlet store. Each panel displays 12 to 18 color characters. Prior to acquisition, the panels had been used for about one-third of their expected lifetimes. The data in the table below (saved in the PANELFAIL file) give the failure times (in years) of the 50 used panels. Use the techniques of this section to determine whether the used panel wear-out times are approximately normally distributed.