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Mathematics · Oct / Nov 2024 · Paper 61 · Question 5

YMA01

As printed in the paper

The question as text

5. Frequency density 0 10 20 30 40 50 Time in hours The histogram shows the number of hours worked in a given week by a group of 64 freelance photographers.

Read automatically from the paper; the printed page above is exact.

Show the answer and mark scheme
  • 5(a)[1]

    [Time is] continuous

    16 photographers = 160 small squares or 64 photographers = 640 small squares

    or 16

    or 64

    or 160

    or 640

  • 5(b)[3]

    160 =

    0.1

    640 =

    0.1

    16 =

    10

    64 =

    10

    Frequency density = 1.6 or Correct scale on the frequency density axis

    x =

    16

    oe or (20 12)

    −

    (24

    −

    20)

    ×

    16

    +

    ×

    14

    240

    160

    10

    5

    = 24

  • 5(c)[2]

    Using n

    Using n + 1

    (32

    21)

    (32.5

    21)

    −

    −

    [

    =

    ]20

    +

    ×

    (25

    −

    20)

    oe

    [

    Q =

    ]

    20

    +

    ×

    (25

    −

    20)

    oe

    Q

    2

    35

    −

    21

    2

    35

    −

    21

    35

    −

    32

    35

    −

    32.5

    or

    25

    (

    25

    20

    )

    oe

    or

    25

    (

    25

    20

    )

    oe

    −

    ×

    −

    −

    ×

    −

    35

    21

    35

    21

    −

    −

    = awrt 23.9

    = awrt 24.1

  • 5(d)[2]

    Mean = Median or Mean ≈ Median

    e.g. Appropriate decision. Consistent with expectation for a normal distribution.

    Notes

    (a)

    B1

    Allow not discrete

    For establishing a ratio between photographers and area or calculating frequency density (may be

    (b)

    M1

    implied by 2nd M1)

    M1

    For a correct ratio or expression using areas for photographers from 12 to 24

    A1

    Cao

    (c)

    M1

    For a correct method to find median using either n or n + 1

    A1

    awrt 23.9 or awrt 24.1 if using n + 1

    For a correct comment about mean and median ft their median

    (d)

    M1

    Allow mean is close to median to imply mean ≈ median

    Ignore any comments made about the shape of the histogram

    For a correct compatible comment about Charlie’s decision ft their median

    If Mean = Median or Mean ≈ Median, then the decision should be that a normal distribution is

    A1ft

    suitable [due to symmetry]

    If Mean < Median or Mean > Median or mean ≠ median, then the decision should be that a

    normal distribution is not suitable [due to the skew in the data]

    [

    ]

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