Shaft graves in ancient Greece. Refer to the American Journal of Archaeology (Jan. 2014) study of sword shaft graves in ancient Greece, Exercise 2.60 (p. 89). The number of sword shafts buried at each of 13 recently discovered grave sites is reproduced in the following table.

1 2 3 1 5 6 2 4 1 2 4 2 9 Source: Harrell, K. “The fallen and their swords: A new explanation for the rise of the shaft graves.” American Journal of Archaeology, Vol. 118, No. 1, January 2014 (Figure 1).

a. Calculate the range of the sample data.

b. Calculate the variance of the sample data.

c. Calculate the standard deviation of the sample data.

d. Which of the measures of variation computed in parts a–c have the same units of measure (number of sword shafts) as the original variable?