The students don't all need to become accomplished statisticians, but they need to realize that experimental measurements give you fuzzy numbers and that there are tools available which let you get the most you can out of these fuzzy numbers. The lab book or journal Have your students keep detailed lab books or journals, with ALL of their data, calculations, observations, etc., in them. This is essential if the mentor is to be of help on rough spots, and it is essential for the final write-up of the project. I know this from bitter personal experience. The training the students get in organizing their thoughts and writing them up accurately and clearly is as important as anything else they may get out of the project.
Technical writing is highly structured and organized.
Only when a good, detailed outline has been prepared and pondered does the student start to write the actual text. With this outline and a complete lab book, the final writing goes very quickly and smoothly. There are a number of good ways to organize the paper. I find the following to be a useful generic outline, although some sections may be omitted and others added if the nature of the project dictates this. It should convince a nonspecialist that you know what you're doing, and, if possible, that this is a pretty neat, exciting project.