Topic: Math - Histogram graphs Objectives: Students will understand the concept of histograms and the importance of using and reading histograms correctly. Students will be able to display and interpret data in a histogram. Materials needed: Print off four graphs for each student. You may use this free PDF from TeacherVision.com: http://www.teachervision.fen.com/tv/printables/bargraph.pdf Have colored pencils or crayons available to each student (optional). Have empty Kleenex boxes or shoe boxes for each group of 3 students. Have scrap pieces of paper, each student needs a piece of paper for each group in the class. Available internet Strategies: Introduction: Before class starts, have the shoe boxes spread around the outside of the room. Each shoe box needs writing utensils and enough scrap paper for each student. Form the class into groups of three students. Have each group think of a numerical question such as “How many hours of sleep did you get last night?” or “How many minutes are your showers?” or “How many hours do you watch TV a day?” or “What is your favorite time of day?” Once they confirm their question with you, have them write that question on a piece of paper and place it next to a shoe box. If some groups finish before other groups, have them discuss how they think that the class will answer their question. The answers do not have to be within any numerical range. Once all of the shoeboxes are ready, each student should go to each question and put their individual answer on the scrap paper and place it in the shoebox. (Each student should individually answer.) Once finished with this, the groups will gather their answers and work through the lesson with teacher direction. (Teachers are encouraged to make their own shoebox as well to help understanding.) Lesson steps: Begin by setting the shoebox activity to the side. Explain the concept of a histogram o Students should know some different types of graphs, such as circle graphs, bar graphs, or line graphs. Review this concept if necessary. o Histograms are another type of graph. It is a bar graph that is used to display and organize data. This bar graph is displayed mostly in equal intervals. That is that the x-axis is not a specific number, but equal groups of numbers. Show students an example of a histogram and explain each part: the title, the y axis is the frequency, and the x-axis is our intervals. You may use this link: http://www.tutorvista.com/q/statistics-analyze-and-interprethistograms/88105/ Explain how to construct a Histogram. This will use the introduction to the lesson. o Organize the answers from smallest to largest numerically. Explain how you would find equal intervals for your question. Then have the groups decide on where to set their intervals. Go around and monitor each group. o Then make a chart. As you fill in your chart, have them fill in theirs as a group. Interval Tallies Frequency o Then construct the bar graph. Construct yours along with the students so that students can follow along, either using a doc camera or smart board. Stop between steps to check for understanding and clarifying. o Use the graphs printed from earlier. Have each student make their own graph of the shoebox activity. o Label the x and y axis and the title o Create the intervals along the x axis o For each interval, draw the bar to the necessary height. o (optional) Students may color these graphs for clarity. Then return to the above link or use your own histogram and ask questions. From the link above, you could ask “What is the difference in the number of directors that make 3-4 movies and 5-6 movies?” or “How many movies, based on this graph, is a director most likely to direct in his/her career?” Answers would be 5 to the first and 3-4 or 11-12. Other questions may be asked. o Ask students to individually make a new histogram to the one in the link. Have the intervals be 0-4, 5-8, 9-12. Students could brainstorm and write down difference they find in the two graphs, the pros and cons of each graph, and which graph would they use. Discuss what they wrote down. Talk about why a graph is more accurate. If conflicting ideas, have them debate their case. Then ask how many directors make 7 movies. The answer would be that there is no way to tell using this graph. Make one more histogram with the students (have them fill their sheets out as well) using this data. Hours of rain in one week in different cities around the United States: 3, 0, 9, 1, 4, 2, 0, 3, 6, 14, 4, 2, 5, 3, 7, 3, 0, 8, 3, 10 o Organize the data: 0, 0, 0, 1, 2, 2, 3, 3, 3, 3, 3, 4, 4, 5, 6, 7, 8, 9, 10, 14 o Make a chart: Interval Tallies Frequency 0-3 IIIIIIIIIII 11 4-6 IIII 4 7-9 III 3 10-12 I 1 13-15 I 1 o Construct a Histogram Finally, ask students about the importance of histograms. Have them journal about how histograms could be used in the world and which occupations make use of this type of graph. Discuss the importance of reading them correctly. Discuss some potential flaws of histograms. o Histograms organize data that is easy to interpret. Many different occupations use histograms to predict outcomes, find stats for athletes, find average salaries, etc. o Reading them correctly means interpreting data correctly. This makes labels extremely important. o Flaws could be in the data, in the labeling, or in the graphing. Just because data is in a histogram does not make it true!! Closure: Explain the assignment to students. Remind them of their project and how this will help their report. Ask for any additional questions, and have them start on their assignment. Assignment: Have students visit http://www.almanac.com/weather/history/states This assignment should be done individually, but they will have their group working on the exact same region if questions arise. On this website, students should enter the location their project group was assigned. They should choose the date of the day that it is today and look at the weather of the past years on that date. Remind students that this is a good start to their project! Students may either make a histogram about the temperature or precipitation. Students should collect data from the past 20 years. If certain students are overwhelmed by how much data 20 years produces, have them collect 10 years or less. The x-axis would be intervals of temperature or precipitation. The y-axis will be the number of years that it reached those intervals. Students should turn in both their chart and graph. Give them time at the end of class to get research done in case some of them do not have internet access at home. If the textbook has a section on histograms, you may assign questions from that chapter to check for understanding and ability to interpret histograms. If the textbook does not have quality questions, ask students questions about their graph that they turn in. These could include: o What is the highest temperature/most rainfall in that city? o What range of temperature or amount of precipitation is most likely? What is the least likely temperature to occur? o What percent of years have a temperature/precipitation in this interval? o In what year was the lowest temperature/precipitation? (Cannot be determined by the graph alone.) Rubric: Category Level 1: Minimal Competency Level 2: Basic Competency Data Students do not have enough data, and their data is incorrect. Students do not complete a histogram. Students have minimal data. Students are not able to answer questions correctly. Histogram Questions Level 3: Advanced Competency Students have most of the necessary data. Level 4: Outstanding Competency Students have necessary data. Students create a histogram without labels or intervals. Students create a correct histogram. Students answer some answers correctly. Students answer most questions correctly and show understanding. Students create a correct histogram that is neat and well organized. Students answer all questions correctly and show understanding. Evaluation: Students will be evaluated through in-class work and observation to show understanding in the importance of correctly using and reading histograms. Students will show ability in creating and displaying a histogram through the assignment with the chart and corresponding graph. Students will also show skills of interpreting graphs correctly through a book assignment or answering questions about their work.