Recall from Example 3 that a household suffers from food in-security if at some point in the year the household eats less, goes hungry, or eats less nutritional meals because there is not enough money for food. The distribution of percentages of households suffering from food insecurity in a U.S. state is unimodal and symmetric with no outliers. North Dakota has the smallest percentage (7.7%), and Mississippi has the largest percentage (22.3%).
a. What is the range of the food insecurity percentages of the 50 states?
b. In Exercise 58, you found that if a distribution is unimodal and symmetric with no outliers, then the standard deviation is approximately R/6, where R is the range. Estimate the standard deviation of6the food insecurity percentages of the 50 states.
c. The actual standard deviation is 2.7 percentage points. Find the error of the result you found in part (b). (The error is the estimated standard deviation minus the actual standard deviation.)