 
 PHY.K02UF Molecular and Solid State Physics  
The mean value of $N$ data points is,
$\large \langle x\rangle = \frac{1}{N}\sum\limits_{i=1}^Nx_i$.
The standard deviation $\Delta x$, is the square root of the mean of the squares $\langle x^2\rangle=\frac{1}{N}\sum x_i^2$ minus the square of the mean $\langle x\rangle^2=\left(\frac{1}{N}\sum x_i\right)^2$.
$\Delta x=\sqrt{\langle x^2\rangle \langle x\rangle^2}$.
The form below will calculate the mean and standard deviation of the column of numbers that are put in the textbox below.

To make the histogram, the interval between $x_{min}$ and $x_{max}$ was divided into 100 bins and each data point was sorted into one of those bins.