Statistics Formulae
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Transcript of Statistics Formulae
STATISTICS FORMULAE
MEASURES OF CENTRAL TENDENCIES (MEAN, MEDIAN AND MODE)
MEAN MEDIAN MODE UNGROUPED DATA ARITHMETIC MEAN (AM)
𝑥 = Σ𝑥𝑛
GEOMETRIC MEAN (GM)
𝑥 = 𝑥!. 𝑥!. 𝑥!…… 𝑥!!
HARMONIC MEAN (HM)
𝐻𝑀 = 𝑛
Σ 1 𝑥 𝑜𝑟
1𝐻𝑀
= Σ 1 𝑥𝑛
UNGROUPED DATA
𝑀𝑒𝑑𝑖𝑎𝑛 =𝑛 + 12
!!
𝑖𝑡𝑒𝑚
UNGROUPED DATA Most frequently occurring value
Or
𝑀𝑜𝑑𝑒 = 3𝑀𝑒𝑑𝑖𝑎𝑛 − 2𝑀𝑒𝑎𝑛
GROUPED DATA ARITHMETIC MEAN (AM)
𝑥 = Σf𝑥𝑛
GROUPED DATA
𝑀𝑒𝑑𝑖𝑎𝑛 = 𝐿 +𝑛2 − 𝐹 𝑐𝑓
GROUPED DATA
𝑀𝑜𝑑𝑒 = 𝐿 +𝑑!𝑐
𝑑! + 𝑑!
MEASURES OF DISPERSION / VARIABILITY
RANGE = 𝑥!"#$% !"#"$ − 𝑥!""#$ !"#"$
MEAN DEVIATION UNGROUPED DATA:
𝑀𝑒𝑎𝑛 𝑑𝑒𝑣𝑖𝑎𝑡𝑖𝑜𝑛 = Σ 𝑥 − 𝑥
𝑛
GROUPED DATA:
𝑀𝑒𝑎𝑛 𝑑𝑒𝑣𝑖𝑎𝑡𝑖𝑜𝑛 = Σf 𝑥 − 𝑥
Σ𝑓
STANDARD DEVIATION UNGROUPED DATA:
𝑆𝑡𝑎𝑛𝑑𝑎𝑟𝑑 𝑑𝑒𝑣𝑖𝑎𝑡𝑖𝑜𝑛 (𝑆 𝑜𝑟 𝜎) = Σ 𝑥 − 𝑥 !
n
GROUPED DATA:
𝑆𝑡𝑎𝑛𝑑𝑎𝑟𝑑 𝑑𝑒𝑣𝑖𝑎𝑡𝑖𝑜𝑛 (𝑆 𝑜𝑟 𝜎) = Σ𝑓 𝑥 − 𝑥 !
Σ𝑓
INTER-‐QUARTILE RANGE = 25th percentile – 75th percentile
CO-‐EFFICIENT OF VARIATION:
𝐶𝑉 = SDMean
𝑋 100 𝑂𝑅 𝜎𝑥𝑋100