What do quantile and var() functions do ?

What is a quartile ? How is it different from quantile ?

Assume that required libraries (Pandas and Numpy) are imported and DataFrame ndf has been created as shown in solved problem 16. Predict the output produced by following code fragment :

print(ndf[ndf["age"] > 30])
print(ndf.head(2)) 
print(ndf.tail(3))

The following DataFrame ndf is from solved problem 16 :

       Name Sex    Position       City  age  Projects  Budget
0    Rabina   F     Manager  Bangalore   30        13      48
1      Evan   M   Programer  New Delhi   27        17      13
2       Jia   F     Manager    Chennai   32        16      32
3     Lalit   M     Manager     Mumbai   40        20      21
4  Jaspreet   M  Programmer    Chennai   28        21      17
5      Suji   F  Programmer  Bangalore   32        14      10

Given the two DataFrames as :

>>> dfc1        
    -   -         
    0   1        
0   2   a      
1   3   b      
2   4   c   

>>> dfc2
    -   -   
    0   1   2
0   2   3   4
2   p   q   r

Why are following statements giving errors ?

(a) print(dfc1 + dfc2)

(b) print(dfc1.sub(dfc2))

(c) print(dfc1 * dfc2)