Class 10, October 6, 2015 Lessons 2.3 & 2.4

 By the end of this lesson, you should understand that: ◦ A relative change is different from an absolute change ◦ A relative measure is always a comparison of two numbers

 By the end of this lesson, you should be able to: ◦ Calculate a relative change ◦ Explain the difference between relative change and absolute change

Source: “2010 Apportionment Results,” United States Census Bureau, (accessed July 29, 2014).

 Main idea: ◦ Change can be discussed as absolute change or relative change  Main idea: ◦ A relative measure is always a comparison of two numbers ◦ One way to show a relative change is to use a percentage increase or decrease. ◦ Using percentages to show relative change is the third way you have used percentages in this class. Previously, you have used percentages to probabilities, or to compare the relative size of two numbers.

 By the end of this lesson, you should understand: ◦ The scale on graphs can change the perception of the information they represent ◦ To fully understand a pie chart, the reference value must be known

 By the end of this lesson, you should be able to: ◦ Calculate relative change from a line graph ◦ Estimate the absolute size of the portions of a pie chart given its reference value ◦ Use data displayed on two graphs to estimate a third value

 Main idea: ◦ It is important to ask questions about and make sense of data  Main idea: ◦ In all relative measures, be aware of the reference value