Students investigate how to extract DNA from kiwi fruit. In one part of the investigation, they use a water bath at 50∘C50^\circ\text{C}50∘C and measure the mass of DNA collected (in milligrams) in three separate trials.
The table below shows their results:
| Trial | Mass of DNA collected (mg) |
|---|---|
| Trial 1 | 28.3 |
| Trial 2 | 29.1 |
| Trial 3 | 28.9 |
Calculate the mean mass of DNA collected. Give your answer to 1 decimal place.