Lesson Title: Is a Sample Ample? Designer: Mary Beth Cook Grade Level: 5 Big Idea: Data Analysis and Probability Essential Question: When is a sample better than counting? How can you estimate the whole set without counting every piece of a larger set? Content Standards: M.O.5.5.2 Students will construct, read, and interpret tables, charts, and graphs including stem and leaf plots to draw reasonable inferences or verify predictions. M.O.5.1.6 Students will model and write equivalencies of fractions, decimals, percents and ratios. M.O.5.5.3 Students will collect and organize real-world data to construct a circle graph (with and without technology), present data and draw conclusions. Learning Skills: 21C.O.5-8.3.LS.1 Student manages emotions and behaviors, engages in collaborative work assignments requiring compromise, and demonstrates flexibility by assuming different roles and responsibilities within various team structures. Technology Tools: 21C.O.5-8.1.TT.1 Student accesses server and/or network resources. Vocabulary: survey, data, sample, random, random sample, circle graph, percents, tally marks, fractions, decimals, estimate, population, set (Vocabulary will be reviewed and discussed during the lesson.) Launch/Introduction: 15 min. 1. Post the essential question and draw students’ attention to it. Ask students to reflect about how they would answer this question. Tell them they will discuss their responses at the end of the class. 2. Post the target vocabulary words and read them with the class. Activate prior knowledge by asking students to explain what they know about each word and how they have previously used the word. 3. Pose this situation to the class. Taking a random sample of a large population is one way to get important information when time, money and other factors do not allow for every single person to be surveyed. Tell students that today they will practice taking a random sample of a larger population or set, but not from people, from…confetti! (toss a small amount of confetti in the air) 4. Using a document camera and LCD projector (or overhead) show a sample of each shape/design in the confetti. Tell students these are sample confetti pieces from a larger bag with thousands of pieces and a variety of shapes. Have students identify and name each shape. (see Teacher Notes). 5. Challenge students with a brief discussion: A survey could be conducted to find out about how many there are of each shape, but it would be time consuming to sort and count every piece. What could we do to get a reasonable idea of about how many of each shape are in the bag? (take a random sample) How can we organize and present the data from the sample so it is easy to read and interpret? (tally chart, bar graph, circle graph) How can we compare data sets of different sizes? (percents, circle graphs) How do we know if our sample accurately reflects the composition of the whole data set? Investigate/Explore 30-40 min. 1. Students work in assigned pairs to complete the investigation activity. Each pair will: Choose a reasonable method for taking the random sample (i.e. take a large pinch of confetti from the bag or randomly divide the contents into several piles and use one pile, etc.) Sort the confetti pieces into like piles by shape attributes. Count the pieces of confetti in each shape sorted pile. Organize and record the data on the Is a Sample Ample? recording sheet. Convert the raw data to fractions, decimals and percents in order to construct and label a circle graph. 2. Students organize their data sets into a circle graph using a template and colored pencils, or a web based data program, i.e. http://nces.ed.gov/nceskids/createagraph/ 3. As pairs complete the activity they post their graphic organizers in a prepared space (front chalkboard or marker board). 4. Students will combine the results of the smaller data sets into a larger class chart. This visual will be helpful as students reflect and respond to the Essential Question during the Summarize/Debrief portion of the lesson, i.e. the larger the sample size, the more likely it is to reflect the composition of the whole set. Summarize/Debrief the Lesson: 30-35 min. 1. Gather students for lesson closure. Use questions and discussion to assess students’ understanding. What method did you use to gather your sample and why? Was your random sample representative of the larger set? How do you know? Did the method you used to take the sample significantly affect the results? Explain. Did your sample size affect the accuracy of your prediction about the larger set? Explain. How could/would a bias affect a random sample? How did you decide to collect and organize your data results? How does your random sample reflect the “whole” or population we used to begin the survey? 2. Refer back to the Essential Question. Discuss students’ reflections. Materials for each pair of students: ½ oz. packets of party/seasonal confetti placed in zip lock baggies OR each student pair may scoop a small sample from a larger container which represents the “whole” or survey population clipboards, circle graph template, graph paper, pencils, colored pencils computer and printer Teacher Notes I used large seasonal or party theme confetti pieces with shapes that are easy to recognize, sort and handle. It is important for the students to see the “whole” or confetti population in one place before they take their random sample, i.e. in a jar or bowl. I assigned student partners/pairs for this activity. You could choose to extend the lesson by guiding students to compare, contrast and analyze the results of the posted data sets and ask questions like: o What conclusions can we draw by comparing each of the data sets? o What conclusions can we draw by contrasting each of the data sets? If the target vocabulary words are unfamiliar, pre-assign students to look up words in a math glossary or student dictionary and share them with the class. During the investigation part of the lesson I rotated in the classroom observing student work, questioning processes and guiding pairs to check their work for reasonableness and accuracy. It was helpful and important for my students to have ground rules for using the confetti during the student Explore Activity. The confetti was to be a tool, not a toy. My students have had prior experience using tally charts and other graphic sources referred to in the lesson. If your students have not, that would be an important prerequisite skill. There are two versions of the recording sheet. The first one can be printed for students to use. The second one has some formatting and formulas built in, so that students can enter data on the spreadsheet and the numbers will be converted to fractions, decimals, and percents automatically. This is meant to be an introduction to some of the things a spreadsheet can do. Students are not expected to master using the format and formula features at this time. If students are using Excel to enter the data, they can display their data as a circle graph showing percents. Sample data and a sample circle graph are included with the Is a Sample Ample? worksheet.