Class 7 Maths Part 2 Chapter 5: Connecting the Dots… (Hinglish Notes)

Ye chapter kis baare mein hai?

Tumhare teacher apne do purane doston se milne waale hain, ek 5 feet lamba aur ek 6 feet, aur tumse poochha jaata hai ki kaun aadmi hai aur kaun aurat. Pakka nahi keh sakte, par anubhav batata hai ki lambi auratein aur chhote aadmi kam milte hain, isliye zyaadatar log ek hi tarah andaaza lagaate hain. Yahi statistical thinking hai: data se ye kehna ki kya hone ki sambhaavna zyaada hai, kya pakka hai ye nahi. Ye chapter data se jawab milne waale sawaal poochhne, numbers ke group ke liye ek number chunne, aur data ko aise draw karne ke baare mein hai ki uski kahaani dikhe.

Statistical sawaal

Statistical sawaal wo hai jiska jawab data ikattha karke milta hai, aur jisme jawab alag alag hone ki ummeed hoti hai. “Hamare school ke Grade 7 students kitne lambe hain?” statistical hai, kyunki har student ki lambaai alag hai. “15 × 4 kitna hai?” nahi hai; uska ek hi pakka jawab hai. Statistics data ikattha karne, use vyavasthit aur analyse karne, aur jo wo dikhata hai use samajhne aur pesh karne ka vishay hai.

Mean: barabar hissa

Ek series mein Shubman ne 5 match mein 110 run banaaye aur Yashasvi ne 4 match mein 96, isliye total ki tulna theek nahi. Har total ko match ki ginti se bhaag do: 110 ÷ 5 = 22 aur 96 ÷ 4 = 24, yaani Yashasvi ne har match mein zyaada run banaaye. (Book mein 110 ÷ 5 = 21 chhapa hai; sahi value 22 hai, aur nateeja wahi rehta hai.) Ye arithmetic mean, yaani average, values ke jod ko values ki ginti se bhaag dene pe milta hai. Ye barabar hissa bhi hai: Shreyas ka 5 logon ka group 30 amrood milaakar barabar baante to har ek ko 6 milte hain. 0 asli value hai aur ginti mein aata hai, par gaayab value, jaise na khela gaya match, chhod di jaati hai. Aur padho mean (average) kaise nikalein? mein.

Median aur outliers

Poovizhi ke parivaar ki lambaai 170, 173, 165, 118 aur 175 cm hai. Inka mean, 160.2 cm, paanch mein se chaar logon ki lambaai se kam hai, kyunki chhote bachche ka 118 cm use neeche kheench leta hai. Baaki se itni door ki value outlier kehlaati hai. Median, yaani sort ki hui values ka beech, 170 cm hai aur parivaar ko kahin behtar dikhata hai. Values ki ginti even ho to median beech ki do values ka average hota hai. Mean aur median ko central tendency ke maap kehte hain, kyunki ye dikhate hain ki values kahan ikatthi hoti hain. Dekho median aur outliers.

Dot plots aur phailaav

Dot plot mein number line ke upar har value ke liye ek dot lagta hai. Isme asli kram kho jaata hai, isliye January ka pyaaz ka daam isse nahi padh sakte, par ek nazar mein sabse chhoti value, sabse badi value aur values ka jhund dikh jaata hai. Pyaaz ke dot plots mein Wahapur ke daam, ₹17 se ₹60 tak, Yahapur ke ₹24 se ₹59 tak waale daamon se zyaada phaile hue hain.

Clustered bar graphs

Do groups ko ek ek category mein compare karne ke liye unke bars ek doosre ke bagal mein banaao: ye clustered bar graph hai, aur har cluster mein do bars hon to double bar graph. Key ke saath rang groups ko alag dikhate hain, aur bars ke andar dots ya tirchhi lines un logon ki madad karti hain jo rang nahi pehchaan paate. Graph mein bahut kuch hota hai, isliye use do step mein padho: pehle pehchaano kya diya hai (banaavat, scale, pattern), phir nateeja nikaalo aur jaancho ki data kaunse daave ko sahi thehraata hai. Padho data ko graph mein kaise dikhayein?

Data detective

Chapter ke aakhir mein 1989, 1999, 2009 aur 2019 mein 5 se 19 saal ke Indian ladkon aur ladkiyon ki average lambaai ki table hai. Dhyaan se padho to dikhta hai ki har umar ke bachche 1989 ke mukaable 2019 mein lambe the, har survey mein 11 aur 12 saal ki umar pe ladkiyan ladkon se thodi lambi thi, aur 13 se ladke aage nikal jaate hain. Achha data kahaani bhi sunaata hai aur naye sawaal bhi uthaata hai. Har sawaal ka jawab, number lock puzzle samet, Part 2 Chapter 5 ke NCERT solutions mein hai.