WISKUNDE
GRAAD 11
NOG OEFENINGE
  
Statistiek : antwoorde
  
MATHEMATICS
GRADE 11
MORE EXERCISES
  
Statistics : answers
  
Antwoorde / Answers  1  
  
    
  
  1.1  

  
           Rangskik / Arrange  :  18 ; 19 ; 19 ; 20 ; 22 ; 24 ; 26
  
  
                                                      18 + 19 + 19 + 20 + 22 + 24 + 26
           Gemiddelde / Mean   =  ──────────────────────
                                                                                 7
  
                                                   148
                                             =  ────
                                                     7
  
  
                                              =  21,143
  
           Mediaan / Median   =  20          |  Waarde presies in die middel  / 
                                                                Value exactly in the middle
  
  
           Modus / Mode   =  19                |  Hoogste frekwensie (2)  / 
  
                                                                Highest frequency (2)
  
  
           Reikwydte/Omvang / Range   =  (maksimum / maximum)  ─   minimum
  
                                                            =  ( 26 − 18 )    =  8
  
                                                                                                                              [ V/Q 1. ]
  
    
  
  1.2  

  
           Rangskik / Arrange  :  11 ; 12 ; 14 ; 16 ; 17 ; 17 ; 18 ; 21 ; 22
  
  
                                                   11 + 12 + 14 + 16 + 17 + 17 + 18 + 21 + 22
           Gemiddelde / Mean   =  ────────────────────────────
                                                                                    9
  
                                                  148
                                             =  ───
                                                    9
  
                                             =  16,444
  
  
           Mediaan / Median   =  17          |  Waarde presies in die middel  / 
                                                                Value exactly in the middle
  
  
           Modus / Mode   =  17                |  Hoogste frekwensie (2)  /  Highest frequency (2)
  
  
           Reikwydte/Omvang / Range   =  (maksimum / maximum)  ─   minimum
  
                                                           =  ( 22 − 11 )    =  11
  
                                                                                                                              [ V/Q 1. ]
  
    
  
  1.3  

  
           Rangskik / Arrange  :  51 ; 52 ; 53 ; 54 ; 56 ; 57 ; 57 ; 57 ; 58 ; 61 ; 62
  
  
                                                   51 + 52 + 53 + 54 + 56 + 57 + 57 + 57 + 58 + 61 + 62
           Gemiddelde / Mean   =  ──────────────────────────────────
                                                                                      11
  
                                                    618
                                             =  ─────
                                                     11
  
                                             =  56,182
  
  
           Mediaan / Median   =  57          |  Waarde presies in die middel  /  Value exactly in the middle
  
  
           Modus / Mode   =  57                |  Hoogste frekwensie (3)  /  Highest frequency (3)
  
  
           Reikwydte/Omvang / Range   =  (maksimum / maximum)  ─   minimum
  
                                                           =  ( 62 − 51 )    =  11
  
                                                                                                                              [ V/Q 1. ]
  
    
  
  1.4  

  
           Rangskik / Arrange  :  10 ; 11 ; 12 ; 12 ; 13 ; 13 ; 14 ; 17
  
  
                                                    10 + 11 + 12 + 12 + 13 + 13 + 14 + 17
           Gemiddelde / Mean   =  ─────────────────────────
                                                                                 8
  
                                                   102
                                             =  ────
                                                     8
  
                                             =  12,75
  
  
           As daar 'n ewe getal waardes is, is die                           If the number of values is an even number,
  
           mediaan die gemiddelde van die                                    then the median is the average/mean of the
  
           twee middelste waardes.                                                two values exactly at the middle.
  
  
  
                                                12 + 13
           Mediaan / Median   =  ───────          |  Ewe aantal waardes, dus gemiddelde van 2 middelste
                                                     2                       waardes
  
                                          =  12,5                      |  Even number of values, thus average of two values
  
                                                                           |  exactly in the middle
  
  
           Modus / Mode   =  12 en / and 13           |  Hoogste frekwensie (2)  /  Highest frequency (2)
  
  
           Reikwydte/Omvang / Range   =  (maksimum / maximum)  ─   minimum
  
                                                          =  ( 17 − 10 )    =  7
  
                                                                                                                              [ V/Q 1. ]
  
    
  
  1.5  

  
           Rangskik / Arrange  :  20 ; 21 ; 22 ; 22 ; 23 ; 24 ; 25 ; 26 ; 28 ; 29
  
  
                                                     20 + 21 + 22 + 22 + 23 + 24 + 25 + 26 + 28 + 29
           Gemiddelde / Mean   =  ────────────────────────────────
                                                                                         10
  
                                                   240
                                             =  ────
                                                    10
  
                                             =  24
  
  
                                                 23 + 24
           Mediaan / Median   =  ───────          |  Ewe aantal waardes, dus gemiddelde van 2 middelste
                                                      2                      waardes
  
                                          =  23,5                  |  Even number of values, thus average of two values
  
                                                                       |  exactly in the middle
  
  
           Modus / Mode   =  22                             |  Hoogste frekwensie (2)  /  Highest frequency (2)
  
  
           Reikwydte/Omvang / Range   =  (maksimum / maximum)  ─   minimum
  
                                                           =  ( 29 − 20 )    =  9
  
                                                                                                                              [ V/Q 1. ]
  
    
  
  1.6  

  
           Rangskik / Arrange  :  12 ; 12 ; 13 ; 13 ; 14 ; 15 ; 17 ; 18
  
  
                                                    12 + 12 + 13 + 13 + 14 + 15 + 17 + 18
           Gemiddelde / Mean   =  ──────────────────────────
                                                                                 8
  
                                                   114
                                             =  ────
                                                     8
  
                                             =  14,25
  
  
                                               13 + 14
           Mediaan / Median   =  ───────        |  Ewe aantal waardes, dus gemiddelde van 2 middelste
                                                      2                    waardes
  
                                        =  13,5                      |  Even number of values, thus average of two values
  
                                                                         |  exactly in the middle
  
  
           Modus / Mode   =  12 en / and 13           |  Hoogste frekwensie (2)  /  Highest frequency (2)
  
  
           Reikwydte/Omvang / Range   =  (maksimum / maximum)  ─   minimum
  
                                                          =  ( 18 − 12 )    =  6
  
                                                                                                                              [ V/Q 1. ]
  
    
  
  1.7  

  
           Rangskik / Arrange  :  1 ; 2 ; 3 ; 4 ; 5 ; 5 ; 6 ; 7 ; 7 ; 7 ; 7 ; 8
  
  
                                                    1 + 2 + 3 + 4 + 5 + 5 + 6 + 7 + 7 + 7 + 7 + 8                  62
           Gemiddelde / Mean   =  ─────────────────────────────      =  ────
                                                                                 12                                                    12
  
                                             =  5,167
  
  
                                                 5 + 6
           Mediaan / Median   =  ───────          |  Ewe aantal waardes, dus gemiddelde van 2 middelste
                                                    2                        waardes
  
                                          =  5,5                        |  Even number of values, thus average of two values
  
                                                                           |  exactly in the middle
  
  
           Modus / Mode   =  7                                |  Hoogste frekwensie (4)  /  Highest frequency (4)
  
  
           Reikwydte/Omvang / Range   =  (maksimum / maximum)  ─   minimum
  
                                                          =  ( 8 − 1 )    =  7
  
                                                                                                                              [ V/Q 1. ]
  
    
  
  1.8  

  
           Rangskik / Arrange  :  25;26;28;30;31;31;31;32;32;33;33;34;36;37;37;38;41;42;42;44;51;57
  
  
           Som / Sum  =  25+26+28+30+31+31+31+32+32+33+33+34+36+37+37+38+41+42+42+44+51+57
  
                               =  791
  
                                                    791
           Gemiddelde / Mean   =  ────      =  35,955
                                                     22
  
  
  
                                                 33 + 34
           Mediaan / Median   =  ───────          |  Ewe aantal waardes, dus gemiddelde van 2 middelste
                                                    2                        waardes
  
                                          =  33,5                      |  Even number of values, thus average of two values
  
                                                                           |  exactly in the middle
  
  
           Modus / Mode   =  31                                |  Hoogste frekwensie (3)  /  Highest frequency (3)
  
  
           Reikwydte/Omvang / Range   =  (maksimum / maximum)  ─   minimum
  
                                                          =  ( 57 − 25 )    =  32
  
                                                                                                                              [ V/Q 1. ]
  
  
Antwoorde / Answers  2  
  
  
    2.1   19   21   21   37   42   43   48                                                                   [ V/Q 2. ]
  
  

    2.2   Omvang / Range  =  (Maksimum / Maximum)  ─  Minimum
  
                                         =  48  ─  19
  
                                         =  29                                                                             [ V/Q 2. ]
  
  

                                                    19 + 21 + 21 + 37 + 42 + 43 + 48               231
    2.3   Gemiddelde / Mean  =  ──────────────────────      =  ────
                                                                             7                                          7
  
                                              =  33                                                                       [ V/Q 2. ]
  
  

    2.4   Mediaan / Median  =  37      . . . middelste waarde / midmost value
                                                                                                                             [ V/Q 2. ]
  
  

    2.5   Modus / Mode  =  21      . . . hoogste frekwensie (2) / highest frequency (2)
  
                                                                                                                              [ V/Q 2. ]
  
  

    2.6   Aantal dae / Numer of days  =  4      . . . gemiddelde / mean = 33            [ V/Q 2. ]
  

    2.7   Aantal dae / Numer of days  =  4      . . . modus / mode = 21                   [ V/Q 2. ]
  

    2.8   Aantal dae / Numer of days  =  3      . . . mediaan / median = 37             [ V/Q 2. ]
  
  
Antwoorde / Answers  3  
  
  
    3.1  
                                                                                 Gemid / Mean    Mediaan / Median    Modus / Mode
  Dogters / Girls      1      2      4      5      5      6      6      7      7      8      8      8      8      9                                     6,00    6,5    8
  Seuns / Boys      1      2      3      4      5      5      7      7      7      8      8                                              5,18    5    7
  Klas / Class      1      1      2      2      3      4      4      5      5      5      5      6      6      7      7      7      7      7      8      8      8      8      8      8      9    5,64    6    8
  
[ V/Q 3. ]



    3.2   Daar is 14 dogters in die klas van 25.
  
                                   14
            P(dogter)  =  ───                      [ V/Q 3. ]
                                   25
  

    3.3   Daar is 9 uit 11 seuns.
  
                                                  9
           P(seun + punt < 8)  =  ───       [ V/Q 3. ]
                                                 11
  

    3.4   Daar is 12 uit 25 leerlinge.
  
                                                      12
            P(leerling + punt > 6)  =  ───
                                                      25
                                                              [ V/Q 3. ]
  

    3.5   Daar is 4 uit 14 dogters.
  
                                                     4
            P(dogter + punt = 8)  =  ───
                                                    14
  
                                                     2
                                              =  ───
                                                     7
                                                              [ V/Q 3. ]
  

    3.6   Daar is 5 uit 11 seuns.
  
                                                        5
            P(seun + punt > 5,18)  =  ───
                                                       11
                                                              [ V/Q 3. ]
  

    3.7   Daar is 11 uit 25 leerlinge.
  
                                                           11
            P(leerling + punt < 5,64)  =  ───
                                                           25
                                                                [ V/Q 3. ]
  

    3.8   Daar is 1 uit 25 leerlinge.
  
                                                       1
            P(leerling + punt > 8)  =  ───
                                                      25
                                                              [ V/Q 3. ]
  

    3.9   Daar is geen seuns nie, 0 uit 11.
  
                                                   0
            P(seun + punt = 6)  =  ───  =  0
                                                  11
                                                              [ V/Q 3. ]
  


    3.2   There are 14 girls in the class of 25.
  
                             14
            P(girl)  =  ───                         [ V/Q 3. ]
                             25
  

    3.3   There are 9 from 11 boys.
  
                                                9
           P(boy + mark < 8)  =  ───      [ V/Q 3. ]
                                               11
  

    3.4   There are 12 from 25 learners.
  
                                                      12
            P(learner + mark > 6)  =  ───
                                                      25
                                                            [ V/Q 3. ]
  

    3.5   There are 4 from 14 girls.
  
                                                4
            P(girl + mark = 8)  =  ───
                                               14
  
                                                2
                                          =  ──
                                                7
                                                             [ V/Q 3. ]
  

    3.6   There are 5 from 11 boyss.
  
                                                      5
            P(boy + mark > 5,18)  =  ───
                                                     11
                                                             [ V/Q 3. ]
  

    3.7   There are 11 from 25 learners.
  
                                                           11
            P(learner + mark < 5,64)  =  ───
                                                           25
                                                            [ V/Q 3. ]
  

    3.8   There is 1 from 25 learners.
  
                                                       1
            P(learner + mark > 8)  =  ───
                                                      25
                                                            [ V/Q 3. ]
  

    3.9   There are no boys, 0 from 11.
  
                                                 0
            P(boy + mark = 6)  =  ───  =  0
                                                11
                                                            [ V/Q 3. ]
  
  
Antwoorde / Answers  4  
  
   4.1
      Telling    Frekwensie (f)    Kumulatiewe Frekwensie
      Tally    Frequency (f)    Cumulative Frequency
    0 ≤ m < 10    ││    2    2
   10 ≤ m < 20    ┼┼┼┼   │    6    8
   20 ≤ m < 30    ┼┼┼┼   ┼┼┼┼   ││    12    20
   30 ≤ m < 40    ┼┼┼┼   ┼┼┼┼   ┼┼┼┼    15    35
   40 ≤ m ≤ 50    ┼┼┼┼   ┼┼┼┼    10    45
  
[ V/Q 4. ]

  
         4.2  Punte is diskreet, kan net
               sekere waardes besit.
                                                              [ V/Q 4. ]
  
         4.3  Onderste klasgrens = 0 en
               boonste klasgrens = <10
                                                              [ V/Q 4. ]

     4.2  The marks are discrete, they
            can only have certain values.
                                                              [ V/Q 4. ]

     4.3  Bottom class bounadry = 0 and
            top class boundary = < 10
                                                              [ V/Q 4. ]
  
          4.4
  

  
[ V/Q 4. ]

  
         4.5.1  8 leerlinge
                                                              [ V/Q 4. ]
  
         4.5.2  12 leerlinge
                                                              [ V/Q 4. ]
  
         4.5.3  10 leerlinge
                                                              [ V/Q 4. ]

     4.5.1  8 pupils
                                                              [ V/Q 4. ]

     4.5.2  12 pupils
                                                              [ V/Q 4. ]

     4.5.3  10 pupils
                                                              [ V/Q 4. ]
  
Antwoorde / Answers  5  
  
   5.1
      Klas middelpunt (x)    Frekwensie (f)    Frekwensie (f.x)    Kumulatiewe frekwensie (kf)    Kumulatiewe frekwensie pereentasie (kf%)
      Class centre (x)    Frequency (f)    Frequency (f.x)    Cumulative frequency (cf)    Cumulatice frequency percentage (cf%)
  
40 ≤ m < 50
  
45
  
10
  
450
  
10
  
20
  
50 ≤ m < 60
  
55
  
15
  
825
  
25
  
50
  
60 ≤ m < 70
  
65
  
20
  
1 300
  
45
  
90
  
70 ≤ m < 80
  
75
  
3
  
225
  
48
  
96
  
80 ≤ m ≤ 90
  
85
  
2
  
170
  
50
  
100
  
  
  
∑f = 50
  
∑fx = 2970
  
50
  
100
  
[ V/Q 5. ]

   5.2
  

  
[ V/Q 5. ]

  
         5.3.1  5 dogters
                                                              [ A 5. ]
  
         5.3.2  25 dogters
                                                              [ A 5. ]
  
         5.3.2  59 kg
                                                              [ A 5. ]

     5.3.1  5 girls
                                                              [ A 5. ]

     5.3.2  25 girls
                                                              [ A 5. ]

     5.3.3  59 kg
                                                              [ A 5. ]
   5.4
  

  
[ V/Q 5. ]

  
         5.5.1  20 %
                                                              [ A 5. ]
  
         5.5.2  70 kg
                                                              [ A 5. ]
  
         5.5.3  mediaan = 60 kg
                                                              [ A 5. ]
  
                                           ∑fx
         5.6  gemiddelde  =  ────
                                           ∑n
  
                                           2 970
                                    =  ──────
                                             50
  
                                   =  59,4
                                                              [ A 5. ]

     5.5.1  20 %
                                                              [ A 5. ]

     5.5.2  70 kg
                                                              [ A 5. ]

     5.5.3  median = 60 kg
                                                              [ A 5. ]

                             ∑fx             2970
     5.6  mean  =  ────    =  ─────
                             ∑cf                50
  
                       =  59,4
  
                                                              [ A 5. ]
  
  
  
  
Antwoorde / Answers  6  
  
  
        6.1   Rangskik die lengtes  /  Arrange the lengths  :
               151  151  151  152  153  153  154  156  157  158  158  159  159
               161  162  162  163  163  164  164  165  165  165  165  165  166  166  167  168
               171  172  172  173  173  175  177  178  179  179  179
    
     6.1.1   Minimum  =  151;      Maksimum / Maximum  =  179
                Omvang / Range  =  Maksimum / Maximum        =  179  ─  151      =  48                      [ A 6. ]
  
    
                                                       6571
     6.1.2   Gemiddelde / Mean  =  ─────      =  164,275
                                                         40                                                                                            [ A 6. ]
    
    6.1.3   Mediaan is die gemiddelde van die 2 middelste waardes (ewe aantal waardes)
               Median is the mean ot the 2 values in the middle (even number of valies)
                                                    164 + 165
               Mediaan / Median  =  ────────       =  164,5
                                                           2                                                                                           [ A 6. ]
    
    6.1.4   Modus is die waarde wat die meeste voorkom.
               Mode is the value wat appears most often.
               Modus / Mode  =  165  (kom 5 keer voor  /  appears 5 times)
                                                                                                                                                         [ A 6. ]
    
    6.2   Mees algemene lengte = 165 cm      (Modus)
            Most common length = 165 cm      (Mode)
                                                                                                                                                         [ A 6. ]
  
    
    6.3  
      Klas middelpunt (x)    Frekwensie (f)    Frekwensie (f.x)    Kumulatiewe frekwensie (kf)    Kumulatiewe frekwensie pereentasie (kf%)
      Class centre (x)    Frequency (f)    Frequency (f.x)    Cumulative frequency (cf)    Cumulatice frequency percentage (cf%)
  
150 ≤ m < 160
  
155
  
13
  
2 015
  
13
  
32,5
  
160 ≤ m < 170
  
165
  
16
  
2 640
  
29
  
72,5
  
170 ≤ m ≤ 180
  
175
  
11
  
1 925
  
40
  
100
  
  
  
∑f = 40
  
∑fx = 6 580
  
∑cf = 40
  
100
  
[ V/Q 6. ]

  
    6.4
  

  
[ V/Q 6. ]

    
                                                                                       ∑fx             6580
    6.5.1   Geskatte gemiddelde / Estimated mean  =  ────    =  ─────
                                                                                        ∑f               40
  
                                                                                =  164,5                                                            [ A 6. ]
    
    6.5.2   Die berekende waarde = 164,275 en die geskatte waarde = 164,5. Die twee waardes is
               dus byna gelyk.
               The calculated value = 162,275 and the estimated value = 164,5. The two values are
               therefore nearly equal.
                                                                                                                                                        [ A 6. ]
  
    
    6.6.1   Maksimum lengte korste 40 %  /  Maximum length of shortest 40 %  =  162 cm             [ A 6. ]
    
    6.6.2   Minimum lengte langste 25 %  /  Minimum length of tallest 25 %  =  171 cm                   [ A 6. ]
    
    6.6.3   Minimum lengte langste 60 %  /  Minimum length of tallest 60 %  =  162 cm                   [ A 6. ]
    
    6.6.4   Stelling is korrek. Die maksimum lengte van korste 40 % is 162 cm.
               60 % is dus langer as 162 cm.
  
               The statement is true. The maximum length of the shortest 40 % is 162 cm.
               60 % ate therefore taller.                                                                                                  [ A 6. ]
    
    6.6.5   Stelling is korrek. 55 % is korter as 166 cm.  /  
               The statement is true. 55 % are shorter than 166 cm.
                                                                                                                                                        [ A 6. ]
  
Antwoorde / Answers  7  
  
  
       
 7.1

     
Frekwensie
  
Kumulatiewe frekwensie
      20 ≤ m < 30   
5
  
5
      30 ≤ m < 40   
6
  
11
      40 ≤ m < 50   
6
  
17
      50 ≤ m < 60   
8
  
25
      60 ≤ m < 70   
7
  
32
      70 ≤ m < 80   
6
  
38
      80 ≤ m ≤ 90   
2
  
40
  
[ A 7. ]

  
        7.2
  

  
[ V/Q 7. ]

  
         7.3  5 leerlinge reis minder as
               30 km per week en
               32 reis minder as 70 km
               per week.
                                                              [ V 7. ]
  
         7.4  15 leerlinge reis 60 km
               per week.
                                                              [ V 7. ]
  
         7.5  NB  Die afstande wat gegee word is
               die afstand wat 'n leerling per week aflê.
               Die leerling reis die afstand 10 keer
               per week. Die gegewe afstand is dus
               10 keer die afstand van die skool af.
  
         7.5.1  Waar. 5 leerlinge reis minder as
                   30 km per week en is dus minder
                   as 3 km van die skool af.
                                                              [ V 7. ]
  
         7.5.2  Vals. Tussen 10 en 12 km van die
                   skool af beteken tussen 100 en
                   120 km per week en daar is geen
                   leerling wat meer as 90 km reis nie.
                                                              [ V 7. ]
  
  
         7.5.3  Waar. 8 leerlinge reis tussen
                   70 en 90 km per week en is dus
                   tussen 7 en 9 km van die skool af.
                                                              [ V 7. ]
  
         7.5.4  Waar. Sewe leerlinge reis tussen
                   60 en 70 km per week en is dus
                   tussen 6 en 7 km van die skool af.
                                                              [ V 7. ]
  
         7.5.5  Vals. Nader as 5 km beteken
                   minder as 50 km per week.
                   Daar is 17 leerlinge wat minder
                   as 50 km per week reis.
                                                              [ V 7. ]
  
         7.5.6  Vals. Twaalf leerlinge reis 30 km
                   en meer maar minder as 50 km
                   per week en dus is hulle tussen
                   3 en 5 km van die skool af.
                                                              [ V 7. ]
  
         7.5.7  Waar. Geen leerling reis meer
                   as 90 km per week nie en is
                   dus minder as 9 km van die skool af.
                                                              [ V 7. ]
  
         7.5.8  Vals. Geen leerling is meer as
                   9 km van die skool af nie, verwys
                   na 7.5.7. Al die leerlinge is dus
                   nader as 9 km van die skool af.
                                                              [ V 7. ]

     7.3  Five pupils travel less than
            30 km per week and
            32 travel less than 70 km
            per week.
                                                          [ Q 7. ]

     7.4  Fifteen pupils travel 60 km
            per week.
                                                          [ Q 7. ]

     7.5  NB  The distances given are the
            distances travelled per week.
            The pupil travels this distance 10 times
            per week. Thus the given distance is
            10 times the distance from the school.

     7.5.1  True. 5 pupils travel less than
               30 km per week and thus are less
               than 3 km from the school.
                                                         [ Q 7. ]

     7.5.2  False. Between 10 and 12 km
               from the school implies that more
               than 100 km and less than 120 km
               must be travelled in a week and
               no pupil travels more then 90 km.
                                                         [ Q 7. ]

     7.5.3  True. Eight pupils travel between 70
               and 90 km per week and thus are
               between 7 and 9 km from the school.
                                                         [ Q 7. ]

     7.5.4  True. Seven pupils travel between 60
               and 70 km per week and thus are
               between 6 and 7 km from the school.
                                                         [ Q 7. ]

     7.5.5  False. Closer than 5 km implies less
               than 50 km per week. There are
               17 pupils that travel less than 50 km
               per week.
                                                         [ Q 7. ]

     7.5.6  False. Twelve pupils travel 30 km and
               more but less than 50 km per week
               and thus live between 3 and 5 km
               from the school.
                                                         [ Q 7. ]

     7.5.7  True. No pupil travels more than
               90 km per week and thus lives
               less than 9 km from the school.
                                                         [ Q 7. ]

     7.5.8  False. No pupil lives more than
               9 km from the school, refer to 7.5.7.
               All pupils thus live closer than
               9 km from the school.
                                                         [ Q 7. ]