An aerospace engineering student is conducting a study to investigate if carrying a high-resolution multispectral sensor package (heavyweight payload) vs a standard visual sensor (lightweight payload) affects the flight endurance of a specific model of quadcopter drone. An independent measures design was used, testing a small group of 14 drones. Half of the drones were flown with the heavyweight payload, while the other half were flown with the lightweight payload. The data representing flight durations (in minutes) before reaching a critical 15% battery threshold is shown in the table below.
| Flight duration (minutes) under different payload conditions | |||
|---|---|---|---|
| Heavyweight Payload | Lightweight Payload | ||
| Drone | Duration | Drone | Duration |
| 1 | 22 | 1 | 28 |
| 2 | 19 | 2 | 31 |
| 3 | 24 | 3 | 29 |
| 4 | 18 | 4 | 26 |
| 5 | 21 | 5 | 34 |
| 6 | 25 | 6 | 27 |
| 7 | 20 | 7 | 32 |
Calculate the mean flight duration for the 'Lightweight Payload' condition and present your findings to 3 significant figures. Show your workings.
