An agricultural scientist is investigating the effect of deficit irrigation on the root development of a new drought-resistant crop variety.
Twelve seedlings in Group X ('Deficit Irrigation') were grown with restricted watering, while twelve different seedlings in Group Y ('Normal Irrigation') were grown under standard watering conditions. After 28 days, the primary root length of each seedling was measured to the nearest millimetre.
The results are shown in Table 1 below.
Table 1: Primary root length (mm) of seedlings
| Group X (Deficit Irrigation) | Group Y (Normal Irrigation) |
|---|---|
| 182 | 284 |
| 165 | 271 |
| 191 | 315 |
| 210 | 290 |
| 174 | 322 |
| 185 | 265 |
| 201 | 301 |
| 169 | 288 |
| 195 | 310 |
| 204 | 279 |
| 180 | 295 |
| 178 | 306 |
State, with justification, the most appropriate measure of central tendency for calculating the average root length for each of the two groups of seedlings in Table 1.
235 exam-style questions on AQA A Level Psychology Data handling and analysis. Each one has a worked solution and a mark scheme showing where the marks go.