The file Market penetration contains the market penetration value (that is, the percentage of the country population that are users) for the 15 countries that lead the world in total number of Facebook users:
50.19 25.45 4.25 18.04 31.66 49.14 39.99 28.29 37.52 28.87
37.73 46.04 52.24 38.06
a. Compute the first quartile (Q\), the third quartile (<23), and the interquartile range.
b. List the five-number summary.
c. Construct a box plot and describe its shape.