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Course: Mathematics — First Preparatory
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Curriculum

Mathematics — First Preparatory

Text lesson

Organizing Data

Mathematics — First Preparatory

Organizing Data

Worked examples

Worked examples

Comparison aspectMain ideaKeywords
Example 1
  • The scores of 12 pupils in a test out of 5 were: 3
  • 4. Make a frequency table
scorespupilstestwere
Solution
  • Count each value with tally marks: the score 2 has frequency 2
  • the score 3 has frequency 3
  • the score 4 has frequency 4
  • and the score 5 has frequency 3. The total of the frequencies is 2 + 3 + 4 + 3 = 12
  • which is the number of pupils
Countvaluetallymarks
Example 2
  • The heights of 10 pupils in centimetres are: 142
  • 150
  • 138
  • 155
  • 147
  • 160
  • 152
  • 141
  • 158
  • 149. Make a frequency table with classes of width 10 cm
heightspupilscentimetresMake
Solution
  • The classes are 130 – less than 140
  • 140 – less than 150
  • 150 – less than 160
  • and 160 – less than 170. The first class has 1 height (138)
  • the second has 4 (142
  • 147
  • 141
  • 149)
  • the third has 4 (150
  • 155
  • 152
  • 158)
  • and the fourth has 1 (160). The total of the frequencies is 1 + 4 + 4 + 1 = 10
classeslessfirstclass
Comparison aspectMain ideaKeywords
Example 3
  • Using the table in Example 1
  • find the percentage of pupils who scored 5
Usingtablefindpercentage
SolutionThree pupils out of 12 scored 5. The percentage is 3/12 = 1/4 = 25%Threepupilsscoredpercentage
Example 4
  • Using the same table
  • how many pupils scored at least 4?
Usingsametablemany
SolutionThe scores 4 and 5 satisfy the condition. Their frequencies add to 4 + 3 = 7 pupilsscoressatisfyconditionfrequencies
Example 5 (the hardest)
  • In the heights example
  • which class contains the largest number of pupils?
heightsclasscontainslargest
Solution
  • The two classes 140 – less than 150 and 150 – less than 160 each have a frequency of 4
  • so they share the largest frequency. We must state both
  • because the table has two equal classes
classeslessfrequencyshare
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