A Sample of 20 Endangered Species Was Obtained and the Length

Multiple Choice

A sample of 20 endangered species was obtained and the length of time (in months) since being placed on the list was recorded for each species. The ordered data follow:
52, 54, 58, 59, 59, 60, 60, 63, 65, 66, 67, 68, 69, 73, 74, 77, 78, 79, 79, 98
What is the mean length of time (in months) since being placed on the list for these 20 species?

A) 66.32
B) 66.50
C) 67.90
D) 68.25