Return a statistical summary of the numeric columns of df: for each
numeric column, report count, mean, standard deviation, min, the 25th/50th/75th
percentiles, and max.
Sample data:
df:
animal age visits priority
a cat 2.5 1 yes
b cat 3.0 3 yes
c snake 0.5 2 no
d dog NaN 3 yes
e dog 5.0 2 no
f cat 2.0 3 no
... (10 rows total)
solve(...)