University of South Florida Javascript Equation Calculator with Plotting Exercise

Hi I need HTML5 and Javascript  code to do the following: Create a Javascript calculator that also has plotting capability. First start by writing the Javascript code/function that can solve the Standard Deviation equation (see word attachment for full equation and instructions). 

Your equation may have one dependent variable (y) and an independent variable (x) that has a range of values.  If the equation has other variables, then the use must be able to enter values for them (please put in a set of seed values in the text box).   Once the code is working, you will then then to us the calculator for plotting.