We have a data set consisting of the aluminum contents of 26 bihourly samples of recycled pet plastic from a recycling facility. those 26 measurements have y = 142.77 ppm and s ≈ 98.2 ppm. use these facts to respond to the following. c) make a 90% upper confidence bound for the mean aluminum content of such speciments over the whole study period. (find a # such that ([infinity], #) is a 90% confidence interval.) how does this value compare to the upper endpoint of your interval from part a)? d) make a 95% upper confidence bound for the mean aluminum content of such speciments over the whole study period. (find a # such that ([infinity], #) is a 95% confidence interval.) how does this value compare to the upper endpoint of your interval from part c)? e) interpret your interval from a) for someone with little statistical background.