In addition to the information Deana gave you regarding past posts on this project, can you let us know if you and your son have downloaded the ImageJ program referenced in the project and are using that to gather the calibration information from the histogram screens? The information to put in the chart is shown in the histogram image and corresponds to the chart headings:
Mean Std. Dev. Min Max Mode
Does the software (or ImageJ) you are using match up to this photo in terms of information provided?
Knowing this will help our Experts better assist.