A student compares the strength of three magnets, A, B and C.
The student hangs a chain of identical steel paper clips from the north pole of each magnet. Only the top paper clip touches the magnet.
The student records the largest number of paper clips that each magnet can hold. The student does this three times for each magnet.
The Table shows the results.
Table
| Magnet | Trial 1 | Trial 2 | Trial 3 | Mean |
|---|---|---|---|---|
| A | 6 | 7 | 6 | 6.3 |
| B | 11 | 4 | 10 | |
| C | 3 | 3 | 4 | 3.3 |
Identify the anomalous result in the Table.
Calculate the mean number of paper clips held by magnet B.
Do not include the anomalous result.
Explain why a chain of paper clips can hang from the magnet even though only the top paper clip touches the magnet.
Suggest one variable the student should control to make this a fair test.