320 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.
420 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
5There 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.
6Bar 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.
7Bar 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
8Methods 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
9A 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
10Total 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.
11Exercise1. 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 £
132. 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
14SUMMARYQualitative 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.