Lesson Notes By Weeks and Term v5 - Grade 4

Lesson Video

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Performance objectives

• Collect data using tally marks and questionnaires.
• Represent data in pictographs with a key.
• Represent data in bar graphs with scales and labels.
• Answer questions using pictographs and bar graphs.

Lesson summary

Data handling is a vital skill that helps us make sense of the world around us. In South Africa, we encounter data every day – from the number of learners in a school, the price of pap and vleis at the local butchery, the different languages spoken in our communities, to the scores of our favourite sports teams. Being able to collect, organize, and represent this information helps us understand patterns, make informed decisions, and even solve problems. For instance, a spaza shop owner can use data about what sells best to decide what to stock, or a farmer can track rainfall data to plan their crops.

Lesson notes

2.1 Collecting Data: Data is information. We can collect data by asking questions, counting things, or making observations. One common method is using a tally chart. A tally chart uses tally marks (groups of five - ||||) to record the number of times something occurs. This makes it easier to count large numbers. We can also use simple questionnaires with closed questions (questions that have a fixed set of answers) to collect data.

Example: Imagine we want to find out the favourite fruit of learners in our class. We can ask each learner to choose from apple, banana, orange, or mango. We create a tally chart with the fruit names as categories. As each learner tells us their favourite, we add a tally mark next to that fruit. After everyone has answered, we count the tally marks to see how many learners chose each fruit. 2.2 Representing Data: Pictographs A pictograph uses pictures or symbols to represent data. Each picture represents a certain number of items, which is defined by the key. It’s VERY important to have a key to understand how much each picture represents.

Example: Let’s say we surveyed 20 learners about their favourite sport: Soccer, Netball, Rugby, and Cricket.

We create a table: | Sport | Number of Learners | | --------- | ------------------ | | Soccer | 8 | | Netball | 6 | | Rugby | 4 | | Cricket | 2 | We can represent this data in a pictograph. Let's use the symbol of a smiling face 😀. Let’s define the key: 😀 = 2 learners.

The pictograph would look like this: | Sport | Pictograph | | --------- | ------------------ | | Soccer | 😀😀😀😀 | | Netball | 😀😀😀 | | Rugby | 😀😀 | | Cricket | 😀 | 2.3 Representing Data: Bar Graphs A bar graph uses bars of different lengths to represent data. The length of each bar corresponds to the quantity of the item.

Bar graphs have two axes: X-axis (horizontal): This usually represents the categories (e.g., types of fruit, sports).

Y-axis (vertical): This represents the number or quantity of each category. We need to choose an appropriate scale for the y-axis. A scale is the range of values used on the axis, and it must be consistent. We also need clear labels for each axis and for each bar.

Example: Using the same sports data from above: We draw two axes. On the x-axis, we write the names of the sports: Soccer, Netball, Rugby, Cricket. On the y-axis, we choose a scale. Since the largest number of learners is 8, we can use a scale of 1 unit representing 1 learner. We label the y-axis "Number of Learners". We draw a bar for each sport, making sure the height of the bar corresponds to the number of learners who chose that sport. For Soccer, the bar goes up to

8. For Netball, it goes up to 6, and so on.

Why this is important: Pictographs and bar graphs visually represent data. This allows us to easily compare the quantities of different items. We can instantly see which sport is the most popular and which is the least popular just by looking at the bars or pictures. Guided Practice (With Solutions)

Question 1: A Grade 4 class conducted a survey about their favourite flavour of ice cream.

The results are shown below: | Flavour | Number of Learners | | ------------- | ------------------ | | Chocolate | 10 | | Vanilla | 5 | | Strawberry | 8 | | Bubblegum | 2 | Represent this data using a pictograph. Use the symbol 🍦 = 2 learners.

Solution: | Flavour | Pictograph | | ------------- | -------------------------- | | Chocolate | 🍦🍦🍦🍦🍦 | | Vanilla | 🍦🍦🍦 | | Strawberry | 🍦🍦🍦🍦 | | Bubblegum | 🍦 | Explanation: For each flavour, we divide the number of learners by 2 (because one ice cream cone represents 2 learners) and draw that many ice cream cones.

Question 2: Use the following tally chart to create a bar graph. The chart shows the number of cars of each colour that passed by the school gate in 10 minutes. | Colour | Tally | | ------ | --------- | | Red | |||| || | | Blue | |||| |||| | | White | |||| | | | Black | |||| |||| ||| | Solution: Red: 7 cars Blue: 9 cars White: 5 cars Black: 13 cars The bar graph would have: X-axis: Colour (Red, Blue, White, Black)

Y-axis: Number of Cars (scale from 0 to 14, going up in 1s). Label the y-axis "Number of Cars". Draw bars for each color with the correct height.

Explanation: Tally up the number of each color. Represent that number as the bar height on the graph.

Question 3: A class recorded the number of sunny, cloudy, and rainy days in a month. The bar graph below shows the results. (Assume a bar graph image is shown. Sunny = 15, Cloudy = 10, Rainy = 5) How many more sunny days were there than rainy days?

Solution: Sunny days: 15 Rainy days: 5 15 - 5 = 10 Answer: There were 10 more sunny days than rainy days.

Explanation: Read the value for sunny and rainy days off the bar graph. Then, subtract the rainy day value from the sunny day value. Independent Practice (Questions Only)

Question 1: Collect data from your family members about their favourite South African dish (e.g., Bobotie, Biltong, Bunny Chow, Shisa Nyama).