SERANG, BANTEN – "Children, our subject matter today is bar charts and pie charts," said Towilah, a math teacher at MTsN 2 in Serang. Then she said: "The learning objective for today is that you understand the technique of analyzing and presenting data with two variables using bar charts."
Then Towilah asked one student to help her write the tally on the board and another student to read out the figures. "Your friend Rina will read out the different weights. Please put your hand up if the weight she reads out is the same as your weight," said Towilah. Rina went through the different weights and Budi wrote down the number of students who shared the same body weight.
The data were grouped in tables by column according to weight, tally, and frequency.
"In front of you there now is a data table showing body weights. Can anyone explain why it's important to present this?" asked Towilah. Two students explained that the presentation of data as a bar chart makes it easier to see the grouping of the data. Another student answered that it was important so we are capable of analyzing the data. Then, Towilah distributed worksheets on creating a bar chart to each group. The students worked in their groups.
Within their groups, the students shared out the tasks. For example, there was the task of finding data on daily mathematics scores, and there was setting up the data grouping on a piece of cardboard. The students drew the X-axis (interval value) and Y axis (number of students) to create a bar chart.
Then the students determined the interval and frequency value for each interval. Then they determined the position for the top of each bar. Finally, they drew the bars for all values and so created a bar chart. The bar chart was attractive and easier for students to analyze. "It makes bar charts fun and not difficult," said a student during his reflection. (Anl)