Sketching a graph of $f(x)$ Given a function $f(x)$ is increasing in the intervals $(-\infty, -1 )$ and $(3, \infty)$, and decreasing in the interval $(-1,3)$ 
If I want to sketch a graph of $f(x)$,  
I know that the maximum point $\implies x=-1$
Minimum Point $\implies x=3$ 
However, let's say given the graph 
$-5<x<5$ 
$-5<y<5$ 
Is there anyway to make the graph nearly accurate from only the given information? 
For example, at which $y$ coordinate point would the maximum and minimum point be at?  Or do I just take a random guess from the given information since I only want to sketch it? 
Here is my sketch - 


You have no information about the $y$ values, so your sketch is fine. There are lots of functions that meet your description.
