Pictogram (Statistics)

1Summary 重點摘要

One picture = a fixed number; see which is the most at a glance.

2Vocabulary cards Vocabulary

3Step by step Steps

1. Step 1: Read the titleWhen looking at a picture graph, read the title first; it tells us what the chart is about and what is being counted. Example: the title 'Our class's favourite fruit' means each row is one kind of fruit and the pictures in the row count people. Why read the title first? The same chart means completely different things under different titles, for example counting people or counting votes. A common mistake is counting the pictures without reading the title, so we do not even know what is being surveyed, and the answer goes the wrong way.
2. Step 2: Read the keyThe key tells how many things one picture stands for, and it is the door to the whole chart. Example: the key says 1 apple picture = 2 classmates; keep this rule in mind while counting, for 1 picture means 2 people and 2 pictures mean 4. Why have a key? When a row holds very many people, drawing one picture for each is troublesome, so one picture standing for 2 or 5 is handier. A common mistake is ignoring the key and taking 1 picture for 1 person, which cuts the count in half at once.
3. Step 3: Count the picturesAfter reading the key, count the pictures row by row; point with a pencil, and write down the picture count of each row as you finish it. Example: the apple row has 4 pictures, so remember 4; the orange row has 3, remember 3, and only start calculating when every row is counted. Why one row at a time? Counting several rows together easily becomes confusing. A common mistake is counting so fast that half a picture is missed; some charts use half a picture for 1 person, so watch for halves while counting.
4. Step 4: Use the keyThe number of pictures must be multiplied by the key to give the real number of people; even without times tables, repeated adding works just as well. Example: if one picture stands for 2 classmates and the apple row has 4 pictures, then 2 + 2 + 2 + 2 = 8, that is 8 classmates; the orange row with 3 pictures gives 2 + 2 + 2 = 6 people. Why convert like this? Because pictures are only symbols, and behind each symbol stand 2 people. A common mistake is taking the picture count as the people count and answering 4 instead of 8; always read the key before calculating.
5. Step 5: Compare the rowsComparing the numbers worked out from each row answers questions about which is liked by the most people and which by the fewest. Example: 8 people like apples and 6 people like oranges; 8 is greater than 6, so apples are the most popular, and comparing the banana row's 4 people, 6 is greater than 4, so oranges come second. Compare the people numbers, not the picture counts. A common mistake is comparing only the lengths of the rows; when rows hold different numbers of pictures this leads the eye astray, and the people numbers are what decide the ranking.
6. Step 6: Find the differenceTo find how many more people one row has than another, use subtraction: take the smaller number from the bigger one, and the answer is the difference in people. Example: 8 people like apples and 6 like oranges; 8 - 6 = 2, so 2 more people like apples than oranges. Why subtract the smaller from the bigger? A difference is never negative, and smaller from bigger would give a negative number, which is not learned yet in Primary One. A common mistake is adding the two numbers, 8 + 6 = 14, which is the total rather than the difference; read whether the question asks 'how many more' or 'how many in all' before writing.

4Diagrams Diagrams

5Worked example Example

6Common mistakes Mistakes

7Quick check Quick check

8Recap Recap

• Read the title, then the key.
• Pictures x key value = real amount.
• Most pictures = most popular.
• Find differences by subtracting.
• Half a picture is half the value.