Cambridge Secondary (7-9). Stage 7. MCE Science. Workbook - Unit 7: Properties of Materials - Question 15

Investigate the strength of different paper samples. Materials: 5 strips each of 4 different types of paper (same size, approximately 20 cm × 5 cm), hole puncher, paper clip, yoghurt tub, string, marbles.

How did you decide how many times to repeat each measurement?