Final answer:
True, % change versus year ago is a good measure for year-over-year comparison as it shows relative performance changes in product groups. It's a frequently used metric in business and finance for gauging performance trends as seen in various types of statistical graphs and surveys.
Step-by-step explanation:
The statement that % change versus year ago is the best data measure for comparing to year ago results for a product group can be considered true. This metric accurately represents the growth or decline in the performance of the product group by showing the relative increase or decrease in values, such as sales, market share, or any other relevant measure, from one year to the next. When analyzing data or a graph of percent change at an annual rate, the ups and downs across a zero line would illustrate these changes effectively, especially during periods like recessions where lower rates are expected.
For instance, a box plot graph can provide insights into different percentiles and distribution of data which reflects on how to interpret quartiles and median values. If a survey indicates a certain percentage, say 50%, it can either be a statistic or parameter depending on the context—whether it's a sample of the whole population or the entire population itself.