Final answer:
The mean score for all ninth graders in the city is likely to be between 67.02 and 68.98, rounded to one decimal place.
Step-by-step explanation:
The mean score for all ninth graders in the city can be calculated using the formula:
Mean = Sum of all scores / Total number of scores
However, since we don't have the actual score data, we can't calculate the mean directly. However, we can estimate the mean score based on the information given. In the first estimate, we have a 90% confidence interval of 67.18 to 68.82. In the second estimate, we have a 95% confidence interval of 67.02 to 68.98. These intervals provide a range within which the true mean score is likely to be.
Based on these estimates, we can say that the mean score for all ninth graders in the city is likely to be between 67.02 and 68.98, rounded to one decimal place.