An article in the Transactions of the Institution of Chemical Engineers (Vol. 34, 1956, pp. 280–293) reported data from an experiment investigating the effect of several 31 F2 process variables on the vapor phase oxidation of naphthalene.

A sample of the percentage mole conversion of naphthalene to maleic anhydride follows: 4.2, 4.7, 4.7, 5.0, 3.8, 3.6, 3.0, 5.1, 3.1, 3.8, 4.8, 4.0, 5.2, 4.3, 2.8, 2.0, 2.8, 3.3, 4.8, 5.0.

(a) Calculate the sample mean.

(b) Calculate the sample variance and sample standard deviation.

(c) Construct a box plot of the data.