A researcher investigated the rate of decomposition of hydrogen peroxide using a manganese(IV) oxide catalyst. The table below displays the volume of oxygen gas evolved after 80 seconds80\text{ seconds}80 seconds across four identical trials:
| Trial | Volume of oxygen collected in cm3\text{cm}^3cm3 |
|---|---|
| Trial 1 | 74.1 |
| Trial 2 | 75.5 |
| Trial 3 | 42.8 |
| Trial 4 | 74.9 |
Calculate the mean volume of gas collected at 80 seconds80\text{ seconds}80 seconds.
Do not include the anomalous result in your calculation.
Give your answer to 3 significant figures.