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Pratinidhi Maan

Class 7 Maths · Chapter 13: Binduon ko Jodna… · NCERT Ganita Prakash section P2 5.2

Seekho

Kabir aur Neel cricket khelte hain. Kabir paanch match mein 23, 7, 10, 52, 18 (kul 110); Neel khele chaar mein 26, 53, 2, —, 15 (kul 96). Match ki ginti alag ho to kul anuchit. Iski jagah mean nikaalo: Kabir 110 ÷ 5 = 22, Neel 96 ÷ 4 = 24.

mean = sum of values ÷ number of values

Mean ek barabar hissa hai: 3, 8, 10, 5, 4 amrood 5 doston mein barabar = 30 ÷ 5 = 6 har ek. Puraane Bharatiya granth ise samamiti, "barabar maap" kehte the. 0 score ek maan hai, par na khela match nahi.

Outliers: ek parivaar ki lambaai 169, 173, 155, 165, 160, 164 cm (mean ≈ 164.3); doosre ki 170, 173, 165, 118, 175 cm (mean 160.2). Doosra parivaar zyaadatar lamba hai, par ek chhota bachcha (118 cm, ek outlier) uska mean 5 mein se 4 lambaaiyon se neeche kheench deta hai.

Median kram mein lage data ka beech ka maan: 118, 165, 170, 173, 175 → 170 cm. Even ginti mein beech ke do ka ausat: 155, 160, 164, 165, 169, 173 → 164.5 cm. Outlier median ko mushkil se hilaata hai. Neecha outlier: mean < median; ooncha: mean > median.

Dot plot har maan ko number line ke upar ek dot dikhaata hai: sabse kam, sabse zyaada, maan kahan jhundte hain aur kitne faile hain, sab dikhta hai. Mean aur median kendriya pravritti ke maap hain; sabse zyaada aur kam ka antar failaav dikhaata hai.

Explore: beech dhoondho.

  1. Amrood 3, 8, 10, 5, 4 barabar baante. Har ek ka hissa (mean) set karo.
  2. 7, 2, 9, 4, 3, 8, 5 ka median set karo.
  3. Lambaai 118, 165, 170, 173, 175 cm: median set karo.

Yaad rakho

  • Mean = jod ÷ ginti (barabar hissa); median = kram mein beech ka maan.
  • Outliers mean ko kheenchte hain par median ko mushkil se hilaate hain.

Quick check

Data: 2, 3, 4, 5, 6, 40. Mean aur median kaise hain?

  1. mean > median
  2. mean < median
  3. mean = median
  4. there is no median
Answer

mean > median. Ooncha outlier 40 mean ko 10 tak kheenchta hai, median 4.5.

Socho

Kya 5.6, 8, 3.1, 12.9, 6.5 ka mean ya median 25 aur 30 ke beech ho sakta hai?

Ek answer

Nahi. Dono hamesha sabse chhote (3.1) aur bade (12.9) ke beech hote hain, kyunki barabar karna ya beech lena kabhi siron se aage nahi jaata.

Practice

Teen levels (easy, medium, hard) ke naye sawaalon se practice karo, kuch hands-on, hints aur hal ke saath. Topic poora karne ke liye pichhle 5 mein se 4 sahi karo.