Answer:
0.65
Explanation:
Confidence interval can be calculated using the Mean and Margin of error with M±ME where
- M is the average expected cold days of typical cold.
- ME is the Margin of error for the confidence interval.
In the question it is given that the researchers reported a 95% confidence interval of 6.9 to 8.2 days for the mean expected duration of typical cold.
The minimum value in the confidence interval is M-ME =6.9
The maximum value in the confidence interval is M+ME=8.2
Then we get 8.2-6.9=1.3=M+ME-(M-ME)=2× ME
From this we get ME=0.65