Final answer:
The estimated average percentage of people with the disease is 43 percent, calculated using the mid-point of the provided range. The U.S. disease rate of 33.9 percent is below this average, and without further data, we cannot determine how unusual this is as the standard deviation cannot be computed.
Step-by-step explanation:
Estimating the Average Percentage of Disease and Analyzing the U.S. Rate
To estimate the average percentage of people with the disease across the countries, we analyze the provided range of percentages (11.4 percent to 74.6 percent). A simplistic approach to estimate the average is to calculate the mid-point of this range. Consequently, adding the lowest value (11.4 percent) to the highest value (74.6 percent) and dividing by two gives us an estimated average of 43 percent (rounded).
The question of whether the U.S. disease rate of 33.9 percent is above or below this average is straightforward; since 33.9 is less than the estimated average of 43 percent, the U.S. rate is below average. Regarding how unusual the U.S. rate is compared to the average, we would need to calculate the standard deviation of the listed rates for a precise answer. Nonetheless, considering the U.S. rate falls within the range, it may not be considered particularly unusual.
Without the individual country rates or a specified distribution, the standard deviation cannot be accurately calculated. Typically, statistical software or a detailed dataset is needed to compute standard deviations for real-world data.