In order to provide additional evidence and extend my investigation to find out more and back up my conclusion, I could perhaps get a machine that would drop and time the fall of each parachute. I could also change the material and see if I get a similar pattern of results. I might consider changing the radius of the parachutes I already have and record the results. Another thing I could change is the height I drop the parachutes from and see if this effects the conclusion I have made, also the weight could affect my idea about air resistance.
One of the important differences between previous educational qualifications (and the earlier grading of A-levels) and the later GCSE qualifications was supposed to be a move from norm-referenced marking to criterion-referenced marking.  On a norm-referenced grading system, fixed percentages of candidates achieve each grade. With criterion-referenced grades, in theory, all candidates who achieve the criteria can achieve the grade. A comparison of a clearly norm-referenced assessment, such as the NFER Cognitive Ability Test or CAT, with GCSE grading seems to show an unexpected correlation, which challenges the idea that the GCSE is a properly criterion-based assessment.