LESSON 4.1 Interpreting Graphs KendallHunt（4.1解释图表KendallHunt课）.pdfVIP

CONDENSED L E S S O N 4.1 Interpreting Graphs In this lesson you will ● interpret graphs that show information about real-world situations ● make a graph that reflects the information in a story ● invent a story that conveys the information in a graph A graph can communicate a lot of information in a concise way. This graph shows the relationship between the number of people in a baseball stadium and the time since the game ended. y m u i d a t s n i e l p o e p f o r e b m u N x Time since game ended (min) The number of people depends on the time since the game ended. So the time in minutes is the independent variable and the number of people is the dependent variable. As the time increases, the number of people decreases linearly, indicating that people are leaving the stadium at a constant rate. The slope is the number of people who leave each minute. The x-intercept represents the time when the stadium is empty. The y-intercept represents the number of people in the stadium at the time the game ends. The example in your book shows a more complicated graph that indicates how the number of cans of juice in a vending machine changes over the course of a typical school day. Study the graph carefully for a few minutes, thinking about what might cause each increase, decrease, and change in slope. Then, work through the example, answering the questions on your own before reading the solutions. The text after the example poses several more questions about the graph. Try to answer each question yourself, and then read the answers below. ● When do students arrive at school? The machine is full until 7 A .M., and then the number of cans decreases fairly quickly. This indicates that students probably begin arriving at around 7 A .M. ● What time do classes begin? The number of c