7 Josh is investigating whether sticking pins into a map at random, while blindfolded, provides a random sample of regions of the map. Josh divides the map into 49 squares of equal size and asks each of 98 friends to stick a pin into the map at random, while blindfolded. He then notes the number of pins in each square. To analyse the results he groups the squares as shown in the diagram.
| D | D | D | D | D | D | D |
| D | C | C | C | C | C | D |
| D | C | B | B | B | C | D |
| D | C | B | A | B | C | D |
| D | C | B | B | B | C | D |
| D | C | C | C | C | C | D |
| D | D | D | D | D | D | D |
The results are summarised in the table.
| Region | A | B | C | D |
| Number of squares | 1 | 8 | 16 | 24 |
| Number of pins | 6 | 21 | 33 | 38 |
- Test at the 10\% significance level whether the use of pins in this way provides a random sample of regions of the map.
- What can be deduced from considering the different contributions to the test statistic?
\section*{OCR}
\section*{Oxford Cambridge and RSA}