Key
Read and interpret graph keys (legends) in Grade 9 math data displays: understand how a key maps symbols, colors, or shading to specific data categories for accurate analysis.
Key Concepts
Property All stem and leaf plots include a key to indicate how to read each stem and leaf. Place value information and units are indicated.
Explanation The key is the secret decoder for your stem and leaf plot! It tells you exactly how to put the stem and leaf back together to read the original number. Without it, you would not know if 5|3 means 53, 5.3, or even 503. Always check the key first so you can correctly interpret the data presented in the plot.
Examples For the entry 8 | 2, a key of 8|2 = 82 years old means the data point is 82. For the same entry 8 | 2, a key of 8|2 = 8.2 cm means the data point is eight and two tenths. For the entry 15 | 0, a key of 15|0 = 150 dollars means the data point is one hundred fifty dollars.
Common Questions
What is a key (legend) in a math graph or chart?
A key, also called a legend, is a guide that explains what each symbol, color, or pattern represents in a graph or chart. Without a key, you cannot correctly interpret what the data categories are.
How do you use a key when reading a stem-and-leaf plot?
In a stem-and-leaf plot, the key shows how to combine the stem and leaf to form actual data values. For example, a key stating '4 | 3 = 43' means the stem 4 and leaf 3 together represent the number 43.
Why is the key essential for interpreting data displays?
Different graphs encode data visually using colors, symbols, or patterns. The key translates these visual codes into meaningful labels, allowing accurate reading of bar graphs, pictographs, and back-to-back stem-and-leaf plots.