Incorporating results of supervised student theses in own thesis
Be explicit. 

Write very carefully what ideas were yours, which experiments were yours and which were not. 

So for exapmle:


  I observed the results of the experiment, from which I hypothesised that X might be true. Fooing that bars would reveal if this was true. Ms Jane Undergrad fooed 8 bars, revealing an expessed of buzzed widgets in some conditions (Figure Y). In a parrallel approach, 8 nature wotisits were collected and the nozzle lengths measured (experiment conducted by Mr. Bob PGT Masters). I analysed this data using the SuperWiz alogrithm and concluded that the hypothesis was true.