Answer:
The confidence interval is between 52.2% and 55.8%
Explanation:
Since the study showed that 54% of the people involved in the study had experienced flu-like symptoms, and the margin of error is 1.8%, which is relatively small margin of error, we can easily come to the confidence interval. Since the margin of error goes both ways, above and below the official percentage, in order to get to the confidence interval we need to deduct the margin of error from the percentage, and also, separately, to add the margin of error to the percentage.
54 - 1.8 = 52.2
So the low border of the confidence level is 52.2%.
54 + 1.8 = 55.8
So the high border of the confidence level is 55.8%.