8.1 Concentrations of uranium 238 were measured in 12 soil samples from a certain region, with the following results in pCi/g (picoCuries per gram):

0.76, 1.90, 1.84, 2.42, 2.01, 1.77, 1.89, 1.56, 0.98, 2.10, 1.41, 1.32 a Construct a boxplot.

b Calculate and s 2 for these data.

c If another soil sample is randomly selected from this region, find an interval in which the uranium concentration measurement should lie with probability at least 0.75. [Hint: Assume the sample mean and variance are good approximations to the population mean and variance and use Tchebysheff’s theorem.]