5 The numbers of each of 9 items sold in two different supermarkets in a week are given in the following table.
| Item | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
| Supermarket \(A\) | 17 | 28 | 41 | 43 | 62 | 69 | 75 | 93 | 115 |
| Supermarket \(B\) | 24 | 7 | 18 | 12 | 47 | 29 | 58 | 42 | 37 |
A researcher wants to test whether there is association between the numbers of these items sold in the two supermarkets.
However, it is known that the collection of data in Supermarket \(B\) was done inaccurately and each of the numbers in the corresponding row of the table could have been in error by as much as 2 items greater or 2 items fewer.
- Explain why Spearman's rank correlation coefficient might be preferred to the use of Pearson's product-moment correlation coefficient in this context.
- Carry out the test at the \(5 \%\) significance level using Spearman's rank correlation coefficient.