• When launching the lesson, it can be tempting to go down the rabbit hole of explaining the features of mortgages and interest rates. Instead, we recommend simply explaining that when you pay a mortgage, you own the home, and home values tend to go up over time. This is how many middle class families have built wealth over time and achieved the American Dream. Therefore, it’s concerning that fewer young adults are buying homes. Why is that? And how does this trend affect their prospects at the American Dream?
• Students can use the formula \( \frac{n+1}{2} \) as a shortcut for finding the middle position (the median’s position) of a data set. For example, for a data set with n = 5 values, the middle position is at \( \frac{5+1}{2} = 3 \) → the 3rd value in the data set. For a data set with n = 6 values, the middle position is at \( \frac{6+1}{2} = 3.5 \) → between the 3rd and 4th values in the data set.
• Because students will spend significant time exploring CODAP in this lesson and in Lesson 1.5, this lesson does not have a mastery check. Instead, measures of center will be addressed in the 1.5 mastery check, along with measures of spread and percentiles. If some accountability measure is needed for completion of this lesson, students might take a screen shot of their CODAP work and submit it.

First, download this lesson's slide deck and handout key to see the prompt and sample responses for the Lesson Starter. Then, check out the additional background notes below.

Instructional routine: Notice & Wonder. The lesson handout provides a Notice & Wonder T-frame for students to capture their notes and ideas. It is important that students recognize the difference between a noticing (observation) and a wondering (question that comes to mind). You can find more background on implementing a Notice & Wonder here.

Purpose & Background: The goal of this Lesson Starter is to recognize the overall growth and recent escalation of real estate prices. As students initially notice and wonder about the graph, they do not have any context. This is intentional to support their consideration of the data, without being influenced by what they know about the housing market. A second slide is included for this Lesson Starter to reveal the title and source. Rather than repeating the Notice & Wonder protocol, discussion may then turn to consider the impact of this knowledge on their recorded noticings and wonderings. Considering first the data, then reflecting on it through the housing context, will provide a level floor for students regardless of whether they have any knowledge about home ownership. This positions students to consider the American Dream through the lens of owning a home throughout the lesson and for the Discussion Question.

• The small sample of home prices from 1970 was taken to match population mean ($26,300) and median ($22,300) home price sales from 1970 in the United States, according to estimates from the Federal Reserve.
• According to the Bureau of Labor Statistics’ inflation calculator, $1 in 1970 had the same buying power as about $8 in 2024. This means that the growth in U.S. median income over those years ($9,853 in 1970 to $90,100 in 2024) has only slightly outpaced inflation. Meanwhile, the growth in median home price ($22,300 in 1970 to $423,000 in 2024) has far outpaced inflation. Source for home price data: Federal Reserve. Source for income data: US Census Bureau (1970 Table 17 and 2024 Table A-1).

• For small data sets like the one discussed in this lesson, calculating measures of center and spread is often unnecessary. Instead, creating a dotplot of the data set and describing it could be considered a more useful analysis. However, when first learning about summary statistics, finding each measure of center (and spread in the next lesson) on a small data set is conceptually helpful. That’s why this lesson utilizes a small data set.
• An additional consideration for use of the mean and the median is how they react to outliers. Their resistance or vulnerability to extreme data values will be discussed in Lesson 1.6, when outliers are formally introduced.