Answer:
0.47%.
Explanation:
We have been given that a research student measured the age of an ice layer at 70 m depth as 425 years. The accepted value reported is 427 years.
We will use error percent formula to solve our given problem.
![\text{Error percentage}=\frac{|\text{Approx value}-\text{Exact value}|}{\text{Exact value}}* 100](https://img.qammunity.org/2020/formulas/mathematics/high-school/ovkhexbcvq85sdbobihtwz56c2f45234ob.png)
![\text{Error percentage}=(|425-427|)/(427)* 100](https://img.qammunity.org/2020/formulas/mathematics/high-school/61jchvmyjzv1lavcm9rhe9zem0nwpo0jjs.png)
![\text{Error percentage}=(|-2|)/(427)* 100](https://img.qammunity.org/2020/formulas/mathematics/high-school/dm92b33x4hop3qgpyruzhqizb42dpwkhc2.png)
![\text{Error percentage}=(2)/(427)* 100](https://img.qammunity.org/2020/formulas/mathematics/high-school/96tdoafom40bpoztsukeh6v3h0xv9reuya.png)
![\text{Error percentage}=0.0046838407494145* 100](https://img.qammunity.org/2020/formulas/mathematics/high-school/7uszu2s1f13nmjc62ih7vnsti8ifp6mfl8.png)
![\text{Error percentage}=0.46838407494145](https://img.qammunity.org/2020/formulas/mathematics/high-school/bi4dqa9va53wd1yvw5t8wrntebz56ebvox.png)
Rounding to two decimal places:
![\text{Error percentage}\approx 0.47](https://img.qammunity.org/2020/formulas/mathematics/high-school/uzd4y76tyofdd2qj4h498txe9udrtyuuqn.png)
Therefore, the percent error of students value is approximately 0.47%.