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The Lumenary
K–2Probability & StatisticsPlanned

Data, tallies and picture graphs

Asking questions, collecting data by counting, sorting answers into categories, recording with tally marks, and showing results in picture graphs.

math.prob.data-and-tallies

Show everything needed to reach this topic

The lesson for this topic has not been written yet. The outline below is part of the curriculum map and has not been reviewed.

Builds on

Counting

Required prerequisites, all the way down: 2

You will learn to

  • Collect answers to a simple question and sort them into categories.
  • Record counts with tally marks and show them in a picture graph or block graph.
  • Answer 'how many more' and 'which is most' questions from a graph.

Definition

  • Data are pieces of information collected to answer a question.
  • A tally mark records one item; tallies are grouped in fives to make counting easier.
  • A picture graph uses one picture for each item, or for a fixed number of items.

Theorem

  • If every answer goes into exactly one category, the category totals add up to the number of answers collected.
  • Comparing categories by the length of a row of pictures is reliable only when the pictures are the same size and evenly spaced.

Common misconceptions

  • Comparing rows of pictures of different sizes by their length.
  • Counting one answer in two categories.

Leads to

Data displays and the mean as a fair share

Optional discoveries