Lesson Notes By Weeks and Term v5 - Grade 4

Lesson Video

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Performance objectives

• Collect data using tally marks.
• Use pictographs to show data.
• Use bar graphs to show data.
• Answer questions about our data.

Lesson summary

Data handling is a crucial skill in mathematics and in everyday life. It teaches us how to collect information, organize it, and make sense of it by presenting it in a clear and understandable way. In South Africa, understanding data is important for making informed decisions about everything from which fruit is most popular at the local market to understanding statistics about our community. This week, we will focus on collecting data using tally charts and representing this data visually using pictographs and bar graphs. We'll also learn to answer simple questions based on the information displayed.

Lesson notes

Data Collection with Tally Charts: A tally chart is a simple way to collect data by making marks. Each time you observe an item or event, you make a mark (usually a vertical line). To make counting easier, we group the tally marks into fives. Four vertical lines are followed by a diagonal line across them ( IIII ) to represent five.

Example: Imagine you are at a tuck shop and you want to find out which cool drink is the most popular. You can use a tally chart. | Cool Drink | Tally Marks | Number of Cool Drinks | | ---------- | ----------- | ----------------------- | | Coke | IIII II | 7 | | Fanta | IIII IIII | 10 | | Sprite | IIII I | 6 | | Cream Soda | III | 3 | Representing Data with Pictographs: A pictograph uses pictures or symbols to represent data. Each picture represents a certain number of items, called the key. The key is VERY important because it tells you what each picture stands for.

Example: Let's represent the cool drink data from above using a pictograph.

Let's say our key is: 1 cool drink = 1 🥤 | Cool Drink | Pictograph | | ---------- | ---------------------------------------------------------------------------------------------------------------------------------------------------- | | Coke | 🥤 🥤 🥤 🥤 🥤 🥤 🥤 | | Fanta | 🥤 🥤 🥤 🥤 🥤 🥤 🥤 🥤 🥤 🥤 | | Sprite | 🥤 🥤 🥤 🥤 🥤 🥤 | | Cream Soda | 🥤 🥤 🥤 | If each picture represented 2 cool drinks, the pictograph would look different: Key: 1 cool drink = 2 🥤 | Cool Drink | Pictograph | | ---------- | ------------------------------------------------------------------------- | | Coke | 🥤 🥤 🥤 🥤 🥤 🥤 (3 and a half icons. You can use half an icon to show half a unit) | | Fanta | 🥤 🥤 🥤 🥤 🥤 | | Sprite | 🥤 🥤 🥤 | | Cream Soda | 🥤 🥤 | Representing Data with Bar Graphs: A bar graph uses bars of different lengths to represent data. The longer the bar, the greater the value it represents.

Bar graphs have two axes (lines): Horizontal axis (x-axis): This axis usually shows the categories you are comparing (e.g., cool drinks).

Vertical axis (y-axis): This axis usually shows the number or amount for each category (e.g., number of cool drinks sold). It's very important to label these axes. Remember to choose an appropriate scale for your y-axis. For example, if your data ranges from 0 to 20, you could use a scale of 1, 2, or

5. Make sure your bars are of consistent width and spaced equally apart.

Example: Representing the cool drink data with a bar graph. [Imagine a bar graph here with the following: X-axis: Coke, Fanta, Sprite, Cream Soda.

Y-axis: Number of cool drinks (0-10). Coke bar goes to 7, Fanta to 10, Sprite to 6, and Cream Soda to 3.] Remember to label the axes "Cool Drinks" and "Number of Cool Drinks Sold" respectively. The bars need to be accurately drawn to their relative heights.

Interpreting Data: Once you have a graph or chart, you can use it to answer questions about the data. Look carefully at the labels, key (for pictographs), and the heights of the bars in a bar graph. You can determine which category has the most, which has the least, and compare the values of different categories. Guided Practice (With Solutions)

Question 1: A class voted for their favorite sport.

Here are the votes: Soccer (8 votes), Netball (6 votes), Rugby (4 votes), Cricket (2 votes). Create a tally chart to represent this data.

Solution: | Sport | Tally Marks | Number of Votes | | --------- | ----------- | --------------- | | Soccer | IIII III | 8 | | Netball | IIII I | 6 | | Rugby | IIII | 4 | | Cricket | II | 2 |

Commentary: This question focuses on the basic skill of recording data using a tally chart. We accurately translate the numerical vote count into appropriate tally marks.

Question 2: Using the data from Question 1, create a pictograph.

Use the key: 1 vote = ⚽ Solution: | Sport | Pictograph | | --------- | --------------------------------------------------------------------------------- | | Soccer | ⚽ ⚽ ⚽ ⚽ ⚽ ⚽ ⚽ ⚽ | | Netball | ⚽ ⚽ ⚽ ⚽ ⚽ ⚽ | | Rugby | ⚽ ⚽ ⚽ ⚽ | | Cricket | ⚽ ⚽ |

Commentary: Here, we are focusing on pictograph representation. We chose an appropriate symbol and accurately depicted the number of votes for each sport using the provided key.

Question 3: Using the data from Question 1, create a bar graph.

Solution: [Imagine a bar graph here: X-axis: Soccer, Netball, Rugby, Cricket.

Y-axis: Number of Votes (0-8). Soccer bar reaches 8, Netball to 6, Rugby to 4, Cricket to 2].

Commentary: This question involves translating the data to a bar graph. It's essential the students label the X and Y axis clearly and accurately draw the bar graph. Independent Practice (Questions Only) A group of learners counted the number of different birds they saw in their garden. They saw 5 Sparrows, 3 Pigeons, 7 Hadeda Ibises, and 2 Doves. Create a tally chart to show this data. Use the data from Question 1 to create a pictograph.

Use the key: 1 bird = 🐦 Use the data from Question 1 to create a bar graph. Remember to label your axes!