Introduction: Why Do You Need This Formula Sheet?

Hello dosto! Agar aap Class 11, Class 12, ya College level par Economics padh rahe hain, toh aapko pata hoga ki Statistics for Economics kitna scoring ho sakta hai agar formulas acche se yaad hoan. Exams ke time par saari books ya notebooks palatna mushkil hota hai. Isliye, humne is blog mein saare crucial formulas ko ek hi jagah compile kar diya hai taaki aapka quick revision asaan ho sake.

1. Measures of Central Tendency (Kendriya Pravriti ke Maap)

Data ke core ya average value ko find out karne ke liye yeh primary formulas use kiye jaate hain:

• Arithmetic Mean (Individual Series): X̄ = ΣX / N
• Arithmetic Mean (Assumed Mean Method): X̄ = A + (Σfd / N)
• Median: Size of [(N + 1) / 2]-th item
• Mode: Z = L + [ (f1 - f0) / (2f1 - f0 - f2) ] × h

2. Measures of Dispersion (Apkaaran ke Maap)

Yeh batate hain ki data kitna spread out ya deviate kar raha hai apne average se:

• Range: L - S (Maximum Value minus Minimum Value)
• Standard Deviation (σ): σ = √[ Σ(X - X̄)² / N ]
• Coefficient of Variation (C.V.): (σ / X̄) × 100 (Consistency check karne ke liye best formula!)

3. Correlation (Sah-sambandh)

Do alag-alag variables ke beech ke relationship ki strength aur direction measure karne ke liye:

• Karl Pearson’s Coefficient of Correlation (r): r = Σ(X - X̄)(Y - Ȳ) / √[ Σ(X - X̄)² · Σ(Y - Ȳ)² ]
• Spearman’s Rank Correlation (R): R = 1 - [ 6Σd² / (N(N² - 1)) ]

4. Index Numbers (Soochank)

Inflation, price level changes, aur economic growth track karne ke important formulas:

• Laspeyres’ Price Index: P₀₁ = [ Σ(p₁q₀) / Σ(p₀q₀) ] × 100
• Paasche’s Price Index: P₀₁ = [ Σ(p₁q₁) / Σ(p₀q₁) ] × 100
• Fisher’s Ideal Index: P₀₁ = √(Laspeyres × Paasche) × 100 (The Golden Formula!)

💡 Pro Exam Tip for Economics Students

In formulas ko sirf read mat karo—ek blank paper lekar khud se likhne ki practice karo. Numerical questions solve karte waqt units aur formulas properly mention karne se exam mein full marks milne ke chances badh jaate hain!