8. Solution. The greatest deviation from the average among the measurements that have been preserved is 39 g, which does not exceed $10 \%$ of the nominal mass of the portion. The deviations of the measurements that cannot be read are less than 39 g: for example, the number 38 ? is not less than 380, so the deviation of the number 38 ? from the average does not exceed 19. Therefore, all deviations are no more than 39 g.

The standard deviation does not exceed the greatest deviation, so the standard deviation is no more than 39 g. The machine does not require repair.
Answer: not required.

## Evaluation Criteria

The solution is complete and correct. Other reasoning is possible. For example, the participant added the missing values in such a way as to not reduce the standard deviation, found the standard deviation of the resulting set, and indicated that the deviation of this set is no greater.

The answer is correct, but there is an assessment of the root mean square deviation from the nominal mass of 400 g, not the standard deviation. Further reasoning is correct.

The solution is incorrect or absent.

3 points

1 point

0 points