Mean (Edexcel GCSE Statistics): Flashcards
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Mean when a frequency is zero: x=2,5 f=4,0
Mean when a frequency is zero: x=2,5 f=4,0
Mean = (4x2 +0x5)/4 = 8÷4 = 2
Find Σfx: x=1,2,3 f=2,3,5
Find Σfx: x=1,2,3 f=2,3,5
Σfx = 2x1+3x2+5x3 = 2+6+15 = 23
Find mean from Σfx=450 and Σf=90
Find mean from Σfx=450 and Σf=90
Mean = 450 ÷ 90 = 5
Work out total frequency: f=4,6,5,3
Work out total frequency: f=4,6,5,3
Σf = 4+6+5+3 = 18
Round mean to 2dp: Σfx=37 Σf=6
Round mean to 2dp: Σfx=37 Σf=6
Mean = 37 ÷ 6 = 6.166... → 6.17
Why include frequencies when finding the mean?
Why include frequencies when finding the mean?
Frequencies weight values by occurrence for true mean
Mean of shoe sizes: 28(8),30(7),32(3),34(2)?
Mean of shoe sizes: 28(8),30(7),32(3),34(2)?
Mean = (8×28+7×30+3×32+2×34)/20 = 598/20 = 29.9
Find f and mean: 4(3),5(4),6(f); Σf=12, Σfx=62?
Find f and mean: 4(3),5(4),6(f); Σf=12, Σfx=62?
f = 5; Mean = 62/12 = 5.1667 ≈ 5.17
Calculate mean: Σfx = 598, Σf = 20
Calculate mean: Σfx = 598, Σf = 20
Mean = 598 ÷ 20 = 29.9