Two groups of students were asked how far they lived from their school. the table below shows the distances in miles:

group a (distance in miles)1 1.589.26.84.54.82.50.76

group b (distance in miles)22.53.231.31.82.431.51.8

which statement best compares the mean distances for the two groups?

a. it is equal for group a and group b.

b. it is greater for group b than group a.

c. its value for group a is double the value for group b.

d. its value for group b is three times the value for group a.