A technician buried cords made from dead plant fibres at random positions in a large tray of moist soil. Each cord was removed on the scheduled day, dried and weighed.
| Cord material | Dry mass when buried / g | Dry mass when removed / g | Time buried / days |
|---|---|---|---|
| Cotton | 36.0 | 25.2 | 18 |
| Jute | 18.0 | 12.6 | 12 |
The technician claimed that the cotton cord had the greater mean percentage loss of its initial mass per day during the trial.
Calculate the mean percentage of initial dry mass lost per day for each cord. Evaluate the technician's claim.
101 exam-style questions on Edexcel GCSE Biology 9.3 Material cycles and decomposition, covering 9.3.1 Cycling of materials through ecosystems, 9.3.2 The carbon cycle, 9.3.3 The water cycle, 9.3.4 The nitrogen cycle, 9.3.5 Indicator species and pollution, 9.3.6 Decomposition in preservation and composting, and 9.3.7 Rate changes in decay of biological material. Each one has a worked solution and a mark scheme showing where the marks go.