Working With Data

Imagine reading through thousands of pages of data collected from the last census: number of people in the household, age, nationality, household income, address, etc. How can all that data makes sense? This topic leads to fun classroom activities that deal with gathering data, displaying data, and summarizing and organizing data. It also links mathematics to the real world. Welcome to the world of mathematics known as statistics.

How is data collected? Surveys, questionnaires, and telephone solicitation are just a few of the ways that data is gathered. From these collections, tallies, graphs, and line plots are created to help reduce the data into meaningful, visual presentations.

However, if data is merely collected and displayed, we would be missing the most important feature, analysis of the collected data. This allows us to summarize, organize, and even make predictions for the future. Analyzing data is essential for the growth of children's mathematical understanding.

Lead students to realize the need for identifying numbers that can accurately represent the entire data set. These numbers, called measures of central tendency, help to condense data into a few numbers. This process of analysis begins in Grade 2 by analyzing the spread in the numbers, from lowest to highest. This idea is known as the range. Another descriptive concept covered at this level is the one piece of data that occurs most frequently. This is known as the mode.

Let's look at an example. The table shows the number of tickets sold at a theater in one week.

Keeping Track and Displaying Data:

Range and Mode:
 Tickets Sold – Week of May 5 Day Monday Tuesday Wednesday Thursday Friday Saturday Sunday Numberof Tickets 127 188 123 220 365 396 365

Notice that the number of tickets sold varied from 123 on Wednesday, to 396 on Saturday. This means that the range of the data is 396 – 123, or 273 tickets. Also notice that on Friday and Sunday the same number of tickets were sold. This means that 365 is the mode; it occurs most frequently. (If a different number of tickets were sold each day, we would say that there was no mode.)

As concepts are developed, help children to connect concepts they learned last year to concepts they are learning this year. Last year, they represented and compared data using tally marks. They also answered questions about a survey. This year they will collect and record data from a picture, a survey, and a tally chart. In addition, they will learn about range and mode.