Final answer:
The best estimate of the average percentage affected by the disease for the mentioned countries is 43%. The United States has a disease rate below average at 33.9%.
Step-by-step explanation:
The best estimate of the average percentage affected by the disease for the countries mentioned in the question would be the average of the highest and lowest rates, which is (11.4 + 74.6)/2 = 43%. The standard deviation for the listed rates can't be determined without more information.
The United States has an average disease rate of 33.9%, so it is below average compared to the calculated average for the countries. The U.S. obesity rate can't be compared to the average rate without the obesity rate data for the countries.