Final answer:
The mean temperature when ice was present can be estimated from Antarctic ice cores, and it represents the average conditions maintaining ice stability in the past. The mean temperature for when any ice is present represents the average temperature during times when ice is present, indicating colder periods. Hence the mean temperature would be -2.67°C.
Step-by-step explanation:
The mean temperature for when any ice is present can be determined by taking the average of the temperatures recorded when ice is present. This mean temperature represents the average temperature during times when ice is present, indicating colder periods. For example, if the recorded temperatures when ice is present are -2°C, -5°C, and -1°C, the mean temperature would be (-2°C + -5°C + -1°C) / 3 = -2.67°C. This mean temperature represents the average temperature during the times when ice was present.