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Statistics Formulas for Class 9 and 10

Last updated at May 29, 2023 by

Here, we list all formulas that are required for Class 9 and 10 Exams

The formula list includes

  • Range
  • Mean
    • Mean of Raw Data
    • Mean of Discrete Data
    • Mean of Grouped Data
  • Median
    • Median of Raw Data
    • Median of Discrete Data
    • Median of Grouped Data
  • Mode
    • Mode of Raw Data
    • Mode of Discrete Data
    • Mode of Grouped Data

 

Range

Range = Maximum value – Minimum Value

 

For data

5, 10, 15, 18, 21, 24, 24, 13, 2, 9, 9, 18, 18, 32, 28, 3, 14, 25, 3, 27

 

Maximum value = 32

Minimum value = 2

 

Thus,

Range = 32 – 2 = 30

 

Mean of Raw, Discrete and Grouped Data

Mean of Raw, Discrete and Grouped Data.jpg

Median of Raw, Discrete and Grouped Data

Statistics Formulas for Class 9 and 10 - Part 2

We can also find median using Ogive curve

We draw less than and more than ogive,

 and their intersection is the median

Mode of Raw, Discrete and Grouped Data

Statistics Formulas for Class 9 and 10 - Part 3

 

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Transcript

Mean of Raw Data π‘₯ Μ… = (π‘†π‘’π‘š π‘œπ‘“ π‘œπ‘π‘ π‘’π‘Ÿπ‘£π‘Žπ‘‘π‘–π‘œπ‘›π‘ )/(π‘π‘’π‘šπ‘π‘’π‘Ÿ π‘œπ‘“ π‘œπ‘π‘ π‘’π‘Ÿπ‘£π‘Žπ‘‘π‘–π‘œπ‘›π‘ ) Mean of Discrete Data π‘₯ Μ… = (βˆ‘β–’γ€–π‘“_𝑖 π‘₯_𝑖 γ€—)/(βˆ‘β–’π‘“_𝑖 ) Mean of Grouped Data Direct Method π‘₯_𝑖 = (π‘ˆπ‘π‘π‘’π‘Ÿ π‘π‘™π‘Žπ‘ π‘  π‘™π‘–π‘šπ‘–π‘‘ + πΏπ‘œπ‘€π‘’π‘Ÿ π‘π‘™π‘Žπ‘ π‘  π‘™π‘–π‘šπ‘–π‘‘)/2 Mean = π‘₯ Μ… = (βˆ‘β–’γ€–π‘“_𝑖 π‘₯_𝑖 γ€—)/(βˆ‘β–’π‘“_𝑖 ) Assumed Mean Method a β†’ middle value of π‘₯_𝑖 column 𝑑_𝑖 = π‘₯_𝑖 βˆ’ a Mean = π‘₯ Μ… = a + (βˆ‘β–’γ€–π‘“_𝑖 𝑑_𝑖 γ€—)/(βˆ‘β–’π‘“_𝑖 ) Step-Deviation Method 𝑒_𝑖 = (π‘₯_𝑖 βˆ’ π‘Ž)/β„Ž h β†’ class size Mean = π‘₯ Μ… = a + (βˆ‘β–’γ€–π‘“_𝑖 𝑒_𝑖 γ€—)/(βˆ‘β–’π‘“_𝑖 ) Γ— h Median Median of Raw Data Write data in ascending/descending order N = Total Number of observations (i) If N is odd Median = ((𝑁 + 1)/2)^π‘‘β„Ž observation (ii) If N is even Median = ((𝑁/2)^π‘‘β„Ž π‘œπ‘π‘ π‘’π‘Ÿπ‘£π‘Žπ‘‘π‘–π‘œπ‘› + (𝑁/2 + 1)^π‘‘β„Ž π‘œπ‘π‘ π‘’π‘Ÿπ‘£π‘Žπ‘‘π‘–π‘œπ‘›)/2 Median of Discrete Data First, we find cumulative frequency (cf) Then, we find 𝑁/2 N = Total number of observations (i) If N is odd Median = Observation where cf is greater than 𝑁/2 (ii) If N is even (𝑁/2)^π‘‘β„Ž π‘œπ‘π‘ π‘’π‘Ÿπ‘£π‘Žπ‘‘π‘–π‘œπ‘› = Observation where cf is equal to 𝑁/2 (𝑁/2 + 1)^π‘‘β„Ž π‘œπ‘π‘ π‘’π‘Ÿπ‘£π‘Žπ‘‘π‘–π‘œπ‘› = Observation where cf is greater than 𝑁/2 Median = ((𝑁/2)^π‘‘β„Ž π‘œπ‘π‘ π‘’π‘Ÿπ‘£π‘Žπ‘‘π‘–π‘œπ‘› + (𝑁/2 + 1)^π‘‘β„Ž π‘œπ‘π‘ π‘’π‘Ÿπ‘£π‘Žπ‘‘π‘–π‘œπ‘›)/2 Median of Grouped Data We use the formula Median = l + ((𝑛/2 βˆ’ 𝑐𝑓))/𝑓 Γ— h where Median class = class with cumulative frequency greater than 𝑁/2 l = lower limit of median class h = class size f = frequency of median class cf = cumulative frequency of class preceding median class Mode Mode of Raw Data We follow these steps Arrange in ascending or descending order Find the element occurring max number of times ∴ Mode = Element occurring maximum number of times Mode of Discrete Data Mode is the data which occurs maximum number of times, ∴ Mode = Data with maximum frequency (fi) Mode of Grouped data We use the formula Mode = l + ((𝑓_1βˆ’ 𝑓_0)/(2 𝑓_1 βˆ’ 𝑓_(0 )βˆ’ 𝑓_2 )) Γ— h where Modal Class = Class with highest frequency l = lower limit of modal class f = frequency of modal class 𝑓_0 = frequency of class preceding modal class 𝑓_2 = frequency of class succeeding modal class h = class size

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.