Bar charts, pictograms, pie charts — drawing and reading

1.3.2 · Maths › Basic Data & Probability

Har chart type kaise draw karte hain

Bar Chart Construction (Step-by-Step Derivation)

Step 1: Axes set up karo

Horizontal axis (x): categories (Apples, Bananas, etc.)
Vertical axis (y): frequency/count ek uniform scale ke saath

Uniform scale kyun? Agar neeche 1 cm = 5 units ho lekin upar 1 cm = 10 units ho, toh bars data ke baare mein jhooth bolenge. Uniform scaling visual proportionality ensure karti hai.

Step 2: Bar heights calculate karo $Bar height = \frac{Value for category}{Scale factor}$

Agar tumhari scale hai "1 cm represents 10 units" aur ek category mein 35 units hain: $Height = \frac{35}{10} = 3.5 cm$

Step 3: Equal widths ke saath bars draw karo, gaps chhodte hue

Figure — Bar charts, pictograms, pie charts — drawing and reading

Pictogram Construction

Step 1: Ek symbol aur uski value choose karo Example: 🚗 = 10 cars

Step 2: Har data value ko symbol value se divide karo $Number of symbols = \frac{Data value}{Value per symbol}$

Step 3: Whole symbols + fractional symbols draw karo

Pie Chart Construction (First Principles Se)

Core principle: Ek full circle = 360°. Har category ko total mein se apne fraction ke proportional angle milta hai.

Step 1: Total nikalo $T = \sum all category values$

Step 2: Har sector ka angle calculate karo $Angle for category i = \frac{Value _{i}}{T} \times 360°$

360° kyun? Ek circle ka rotation 360° define hota hai. Ye formula ek fraction ko degrees mein convert karta hai.

Step 3: Sectors draw karne ke liye protractor use karo, 12 o'clock se start karke, clockwise jaate hue

Charts padhna (data extract karna)

Bar Charts Padhna

Bar ki height = value (agar scale di gayi ho toh multiply karo)
Bars compare karo: unchi bar = zyada value
Difference nikalo: bar heights subtract karo

Pictograms Padhna

Symbols count karo × value per symbol
Partial symbols ke liye, fraction estimate karo

Pie Charts Padhna

Sector ka angle measure karo (ya diya hua percentage use karo)
Value calculate karo: $Value = \frac{θ}{360°} \times Total$

Har chart kab use karein

Hamesha pie charts kyun use nahi karte? Agar 15 categories hain, toh pie ek cluttered mess ban jaata hai. Bar charts kaafi categories ko behtar handle karte hain.

Recall Ek 12-saal ke bachche ko samjhao

Socho tum aur tumhare doston ne Halloween par candies collect kiye. Tum dikhana chahte ho kisne sabse zyada liye!

Ek bar chart sabki candy piles ko line up karne jaisa hai aur instantly dekhna hai kiska tower sabse uncha hai. Har person ko apna bar milta hai.

Ek pictogram candy emojis 🍬 use karne jaisa hai jahan 1 emoji = 10 real candies. Agar tumne 35 candies liye, tum 3 full emojis + half emoji draw karte ho. Ye cuter hai aur apne chhote bhai-behan ko dikhana aasaan hai.

Ek pie chart tab use hota hai jab tum dikhana chahte ho ki tumhara candy stash kaise break down hota hai: "Meri aadhi candies chocolate hain 🍫, ek quarter gummies 🍬 hain, aur ek quarter sour cheezein hain 🍋." Tum ek circle ko pizza jaisa kaatte ho, aur har slice dikhata hai ki tumhari total haul ka har type kitna fraction hai.

Key point: bar/pictogram alag logon ko compare karta hai, pie ek insaan ki collection ka breakdown dikhata hai!

Connections

Frequency tables — raw data jo in charts mein jaata hai
Averages and range — statistics jo tum bars se visualize kar sakte ho
Fractions and percentages — pie charts fractions ko angles mein convert karte hain
Ratio and proportion — pictogram symbols ko scale karna ratios use karta hai
Angles — pie charts mein precise angle measurement chahiye
Data collection methods — jahan se charts ke liye data aata hai

Flashcards

Bar chart kya hota hai? :: Ek chart jo rectangular bars use karta hai jahan length value ke proportional hoti hai, distinct categories ke liye bars ke beech gaps hote hain.

Pictogram kya hota hai?

Ek chart jo chhoti icons/pictures use karta hai jahan har icon units ki ek fixed number represent karta hai; fractional icons fractional amounts dikhate hain.

Pie chart kya hota hai?

Ek circular chart jo sectors mein divided hota hai jahan har sector ka angle whole ke fraction ke proportional hota hai (full circle = 360°).

Scale ke saath bar height ka formula :: Bar height = Value ÷ Scale factor (jaise agar scale 1 cm = 10 units hai, value 40 → height = 4 cm)

Pictogram symbols ki number ka formula

Number of symbols = Data value ÷ Value per symbol

Pie chart sector angle ka formula

Angle = (Category value ÷ Total) × 360°

Agar ek pie chart sector 120° ka hai aur total 90 items hain, toh us sector mein kitne items hain?

(120° ÷ 360°) × 90 = (1/3) × 90 = 30 items

Bar charts ke liye uniform scale kyun use karni chahiye?

Visual proportionality ensure karne ke liye; non-uniform scales comparisons ko distort karti hain aur data ko misrepresent karti hain.

Common mistake: pictograms padhte waqt kya yaad rakhna chahiye

Hamesha key check karo ki har symbol kya value represent karta hai, phir multiply karo (sirf symbols mat gino).

Bar chart vs pie chart kab use karein

Bar chart: distinct categories compare karne ke liye; Pie chart: ek whole ke parts dikhane ke liye (proportions/percentages).