The Bureau of Labor Statistics website (www.bls.gov) provides data on month-to-month changes in the U.S. export index for agricultural commodities during 2015. These data are reproduced here:

Month ................................................ Change in Index
Jan .................................................................  -1.1
Feb .................................................................   0.1
Mar ................................................................. -1.4
Apr .................................................................  -2.5
May ................................................................. 1.0
Jun .................................................................  -1.6
Jul .................................................................   -1.3
Aug ................................................................. -0.9
Sep ................................................................. -1.6
Oct .................................................................  -2.2
Nov ................................................................. -1.4

a. Calculate the mean, standard deviation, and interquartile range for these data.
b. Consider the mean calculated in part a. What does this value indicate about the price index?
c. What does the standard deviation indicate about the price index?