8/16/2019 cumulative frequency diagrams.ppt

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Cumulative Frequency

Diagrams & Box Plots

OCR Stage 8

8/16/2019 cumulative frequency diagrams.ppt

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Cumulative Frequency

Time

t minutes0≤t! !≤t"0 "0≤t"! "!≤t#0 #0≤t#!

$um%er ostu'ents

"0 "( )0 ## #

CumulativeFrequency

10 26 56 78 80

8/16/2019 cumulative frequency diagrams.ppt

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5 10 15 20 25 t mins

Cum freq

20

40

60

80

x

x

x

xx

Median = Middle Value

QUARTI!"*#$er Quar%ile = & $a'

*U((er Quar%ile = ) $a'

In%erquar%ile Ran*e

8+ 15+12+

= 15+ , 8+ = 7 min-

% minu%e- 0.%/5 5.%/10 10.%/15 15.%/20 20.%/25

C 10 26 56 78 80

8/16/2019 cumulative frequency diagrams.ppt

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Box Plot

5 10 15 20 25 t mins0

+o,est value -ig.est value/e'ian

+o,er uartile122er uartile

8/16/2019 cumulative frequency diagrams.ppt

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   C  u  m    &

  r  e

  q

Com2aring # sets o 'ata

Median = 62*

#$er Quar%ile = 52*

U((er Quar%ile = 70*

In%erquar%ile ran*e

 = 70 52 = 18*

8/16/2019 cumulative frequency diagrams.ppt

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   C  u  m    &

  r  e  q

Com2aring # sets o 'ata

Median = 78*

#$er Quar%ile = 66*

U((er Quar%ile = 83*

In%erquar%ile ran*e

 = 83 66 = 2*

8/16/2019 cumulative frequency diagrams.ppt

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Box Plots

40 60 80 100 120 m kg 20

IQR-18

2M!IA" 78 and 62

9"

:IR"

Median = 78*

#$er Quar%ile = 66*

;i*

8/16/2019 cumulative frequency diagrams.ppt

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Com2arison statements

* Boys .ave a larger /3D45$ so

 6  on average7 t.ey are .eavier t.an girls

 6 t.e average %oy is "(g .eavier t.an t.e

average girl

* Boys .ave larger 4nterquartile Range so

 6 %oys9 ,eig.ts vary more t.an girls9 ,eig.ts

* :.y 'o ,e $OT use t.e Range;

 6 One extreme value can 'istort t.e com2arison