In the paper "Injuries and Risk Factors in a 100-Mile (161-km) Infantry Road March" (Preventative Medicine, Vol. 28, pp. 167-173), K. Reynolds et al. reported on a study commissioned by the U.S. Army. The purpose of the study was to improve medical planning and identify risk factors during multiple-day road patrols by examining the acute effects of long distance marches by light-infantry soldiers. Each soldier carried a standard U.S. Army rucksack, Meal-Ready-to-Eat packages, and other field equipment. A sample of 10 participating soldiers revealed the following data on total load mass, in kilograms.

a. Obtain the sample mean of these 10 load masses.
b. Obtain the range of the load masses.
c. Obtain the sample standard deviation of the load masses.