3 20 5 35 40 Diagrams are often used to show information from data. e.g. The following data set shows the number of cars given parking tickets on a particular street on 5 weekdays.MondayTuesdayWednesdayThursdayFriday2053540As always, the frequencies are numbers, but we don’t have numbers for the days of the week.The data are qualitative (descriptions ) instead of quantitative (quantities or numbers ).Both types of data can be shown in pictograms and bar charts.
4 20 5 35 40 20 Number of Parking Tickets e.g. A pictogram of the data. MondayTuesdayWednesdayThursdayFriday205354020e.g. A pictogram of the data.Number of Parking Ticketspictogram pictureFridayThursdayWednesdayTuesdayMondayDecide with your partner how many real cars are represented by a picture of a car.Key: = 10 carsThe diagram must have a title and key.Ans: 10
5 There is very little difference between a pictogram and a bar chart. We replace the pictures with bars !Number of Parking TicketsFridayThursdayWednesdayTuesdayMonday10203040As before, we must have a title but instead of a key we have a scale.Bar charts are easier to draw using squared paper.
6 Bar charts are often drawn with the bars going up the page. 40Number of Parking Tickets102030MondayTuesdayWednesdayThursdayFriday40Number of Parking Tickets102030FridayThursdayWednesdayTuesdayMondayFridayThursdayWednesdayTuesdayMondayNumber of Parking Tickets10203040FridayThursdayWednesdayTuesdayMondayNumber of Parking Tickets10203040FridayThursdayWednesdayTuesdayMondayNumber of Parking Tickets10203040To find the mean number of tickets issued per day, we sum the frequencies and divide by the number of days.
7 Bar charts are often drawn with the bars going up the page. Number of Parking TicketsFridayThursdayWednesdayTuesdayMondayNumber of Parking Tickets10203040FridayThursdayWednesdayTuesdayMondayNumber of Parking Tickets1020304040302010mean number of tickets issued per dayFridayMondayTuesdayThursdayWednesday20 +20 +5 +35 +40== 245
8 Methods of Transport to School Double, or dual, bar charts can be used to compare data.This chart compares the way that boys and girls in a junior class travelled to school.Frequency24681012BusTrainTaxiWalkingMethods of Transport to SchoolBoysGirlsWith your partner answer the following:(a) How many girls go by train?(b) How many children go by taxi?(c) What is the most popular way of getting to school?Ans: (a) 2 (b) 4 (c) Walking
9 A line graph is mostly used when data are given at regular intervals of time. For example, times of day, months, or years.YearNumber (millions)199115.1199318.4199519.2199716.5199914.8200112.6e.g. The table shows the total number of recorded crimes in England and Wales.Draw a line graph to display the data.Solution: We plot the years on the x-axis (horizontally) and the number of crimes up the y-axis (vertically). The points are joined with straight line segments.Source: Office for National Statistics: British Crime Survey, Home Office
10 Total Number of Crimes committed in England and Wales Solution:Total Number of Crimes committed in England and WalesYearNumber (millions)199115.1199318.4199519.2199716.5199914.8200112.6xxxxxxNumber (millions)199119931995199719992001YearBetween 1991 and 2001, most crimes occurred in 1995.Crime decreased each year from 1995 to 2001.( Other answers are possible. )Tell your partner 2 things the graph tells you about the number of crimes.
11 Exercise1. The diagram shows the spending by overseas tourists in parts of the U.K. in 2001.SW EnglandHeart of EnglandWalesScotlandAreaSource: Office for National StatisticsKey: = £100 million(a) How much was spent by the tourists in (i) the Heart of England and (ii) Wales?(b) The figure for SW England was £ How many pictures would show this?
12 (i) £700 million was spent in the Heart of England ExerciseAnswers:AreaScotlandWalesHeart of EnglandSW EnglandSource: Office for National StatisticsKey: = £100 million(i) £700 million was spent in the Heart of England(ii) £250 million was spent in Wales.(b) 4½ pictures are needed to show £
13 2. The diagram shows the estimates of fish stock in the North Sea in the 1970s and 1990s. North Sea Fish Stocks100020003000CodHerringHaddockFrequency( thousands of tonnes )70's90'sSource: Office for National Statistics(a) Which type of fish stock increased between the 1970s and the 1990s?Ans:Herring(b) What was the estimate of the stock of cod in the 1970s?Ans: ( 800 thousand ) tonnes
14 SUMMARYQualitative data has descriptions instead of numbers.e.g. days of the week, colours, transport methods.Pictograms and bar charts can be used to display qualitative and quantitative data.Pictograms must have a title and a key. The key gives the frequency for each picture.The lengths of the bars on a bar chart give the frequencies. Bar charts must have a title and a scale.Line graphs have straight line segments joining the points. The x-axis often shows time.