WRITING TASK 1

1. WRITING TASK 1 PIE CHARTS …continued Dec 31st 2012

2. Language input 3 A pie chart makes use of sectors in a circle. • A full circle is 360o. The angle of a sector is proportional to the frequency of the data. The formula to determine the angle of a sector is: • Angle of sector = Frequency of data x 360o Total frequency • Percentage = Frequency of data x 100% • Total frequency • Proportion/ ratio = It can be written in two ways: • using a fraction = a • b • or, • using a colon = a:b

3. Examples

4. Example: The hobbies of 24 students are as follows: Singing - 9 pupils Reading - 3 pupils Dancing - 5 pupils Travelling - 7 pupils

8. LET’S TRY THIS! DRAWING PIE CHARTS BASED ON: ANGLES PERCENTAGES

9. One day 150 packets of chips are dispensed by a vending machine.Draw a pie chart showing the angle of each flavour dispensed. • Salt and Vinegar - 60 packets • Plain - 45 packets • Cheese and Onion - 30 packets • Hot and Spicy - 15 packets

10. ANGLES

11. A sales person sold 80 pairs of jeans in a week. • Draw a pie chart showing this information in percentage. • Monday – 12 • Tuesday – 8 • Wednesday – 8 • Thursday – 36 • Friday – 16

12. PERCENTAGE

13. LET’S PRACTICE CALCULATING FREQUENCY

14. FREQUENCY

15. Mary asked her students to name their favorite pet. The results are shown in the pie chart: If there were 800 students in the school, how many said their favorite pet was fish?

16. ANSWER The total percentage for all the other types of pet= 36% + 28% + 7% + 6% + 11% + 8%= 96%Therefore, the percentage who said their favorite pet was fish= 100% - 96%= 4%Therefore, the number who said their favorite pet was fish= 4% of 800 = (4/100) × 800 = 32

17. Mary asked her students to name their favorite pet. The results are shown in the pie chart: If 720 students said their favorite pet was dog, how many of them said their favorite pet was rabbit?

18. ANSWER 36% of them said their favorite pet was dog36% of the school population = 720⇒ 1% of the school population = 720/36 = 20⇒ 7% x 20 = 140

19. This pie chart shows household expenditure for Jennie: If her expenditure on food is $300 per week, what is the weekly expenditure on transport?

20. ANSWER Method 1: The angle for food is 120°, the angle for transport is 50° She spends $300 on food. = 50 x $300 = $125 120 Method 2: The angle for food is 120°, which is 1/3 of 360° So the total weekly expenditure = 3 × $300 = $900 The angle for transport is 50° = 50 x $900 = $125 360

21. LET’S PRACTICE CALCULATING ANGLE

22. ANGLE

23. The pie chart shows the amount of time each day Belle spends on various activities. What is the angle for the sector of the pie chart representing the time she spends sleeping?

24. ANSWER She spends 25% of her time sleeping. So the angle for the sector of the pie chart representing the time she spends sleeping = 25% of 360°= 90°

25. LET’S PRACTICE CALCULATING PERCENTAGE

26. PERCENTAGE

27. The pie chart shows a family's household expenditure is divided into several categories. What percentage of the family's income is spent on power?

28. ANSWER The angle representing Power = 360° - (120° + 60° + 50° + 55° + 35°) = 360° - 320° = 40° So the percentage spent on Power = 40 x 100 % = 11.1% 360

29. Activity 3 Question I Question II Question III

30. ANSWERS QUESTION I The total number of graduate and postgraduate students at institute S = (14% of 27300) + (21% of 24700) = 3822 + 5187 = 9009 2. Students at N institute = 12% of 27300 = 3276 Students at R institute = 17% of 27300 = 4641 Total students N + R = 3276 + 4641 = 7917 3. Students at M institute = 8% of 24700 = 1976 Students at Q institute = 13% of 24700 = 3211 Total students M + Q = 5187

31. ANSWERS • QUESTION II (A) • The most common method of travel is bus as this has the largest sector on the pie chart. • 1/4 of the students travel by car. • 6 employees travel by car, and this is 1/4 of the total. Therefore, 24 people participated in the survey.

32. ANSWERS QUESTION II (B) 1. Vegetarian sausages account for 1/4 of the total sales, so calculate 1/4 of 3600.1/4 × 3600 = 900. Therefore, 900 packets of vegetarian sausages were sold last month. 2. There are 360° in a complete turn.The 'beef' sector has an angle of 150°, so the beef sector is 150/360th of the circle. 150/360 x 3600 = 1500. Therefore, 1500packets of beef sausages were sold.

33. ANSWERS • QUESTION III • Total percentage = (10 / 24) x 100 = 41.6666667 % • 20 + 10 = 30% is made up of either bones or skin. Hence, 70% is made up of neither. • It cannot be determined since the respective distributions are not known.

34. Activity 4 Fill in the blanks with words from the box.

35. ANSWERS 1. In 1970, coal production comprised 46% of US electricity production. 2. Almost a quarter of US electricity in 1970 was produced using natural gas. 3. Hydro-electric power stations made up just over 16% of US power in 1970. 4. Nuclear power supplied less than 2% of US electricity supplies in 1970. 5. The main fuel used to generate electricity in 1970 in the US was coal.6. Almost half of US electricity in 1970 camefrom coal. 7. About one-eighth of US electricity came from oil-fired power stations. 8. Gas and coal provided three-quarters of US electricity in 1970. 9. Nuclear power contributed a tiny proportion of US electricity in 1970. 10. Renewable sources of electricity, such as hydroelectric power, made up less than 17% of US electricity in 1970. 11. Gas and oil accounted for just over a third of US electric power.

36. ANY QUESTIONS?

37. Let’s continue with TABLES