Here is the histogram of Mantle's home run distribution:

The distribution is not symmetrical – it is right–skewed. 52 and 54 are possible outliers. The center of the distribution is the median (28.5) and the spread is 15 – 54 or you can use Q₁ – Q₃ from the five number summary: 21 – 37.

NOTE: The latter is a better measure of the spread because it is a resistant measure of the spread.