Table 2.18 shows the differences in obesity rates (called Rate Change in the table) for the years 2010 and 1997 for each of the 50 states and the District of Columbia. The obesity rate is the percentage of people having a body mass index (BMI) of 30 or higher. Figure 2.28 is a dotplot of these data.

Figure 2.28 Dotplot of obesity rate change (year 2010 minus year 1997).
a. By looking at the dotplot, what value would you provide if asked to report a typical obesity rate change? Why did you choose this value?
b. What number do you feel most accurately represents the number of outliers in this data set: 0, 1, 3, 5, 6, or 7? Explain your reasoning, including the identification of the observations, if any, that you feel are outliers.
c. Would you classify this distribution as being skewed to the left, skewed to the right, or approximately symmetric? Explain.
d. The largest increase in the obesity rate during this period took place in Oklahoma (15.3), while the smallest increase took place in Alaska (4.8). Explain why this information should not lead you to conclude that Oklahoma had the highest obesity rate in 2010 and that Alaska had the lowest obesity rate in 2010. (Note: The highest and lowest obesity rates in 2010 were in Mississippi and Colorado, respectively.)

Rate Change State Rate Change State Rate Change Massachusetts Connecticut South Carolina 2 8.4 Wisconsin 14.7 North Carolina Wyoming 5.6 7.0 8.4 9.8 11.2 12.6 14.0 15.4 Obesity rate change