Statistics
RD Sharma
CBSE
Grade 10
Question:
Find the median of the following frequency distribution:
Class: 0-10, 10-20, 20-30, 30-40, 40-50
Frequency: 5, 8, 20, 15, 2
Step-by-Step Solution
Key Concept: $N = 50 \Rightarrow N/2 = 25$. $cf$: 5, 13, 33, 48, 50. Median class $20-30$ ($l = 20, cf = 13, f = 20, h = 10$).<br>$\text{Median} = 20 + \left(\dfrac{25 - 13}{20}\right) \times 10 = 20 + \dfrac{12}{2} = 26$.
$N/2 = 25 \Rightarrow$ Median class $20-30$ ($l=20, cf=13, f=20, h=10$). [0.5 Mark]
$\text{Median} = 20 + \left(\dfrac{12}{20}\right) \times 10 = 20 + 6 = 26$. [1.5 Marks]
---
🎯 Official CBSE Marking Scheme:
Finding median class $20-30$: 0.5 Mark
Evaluating median $= 26$: 1.5 Marks
Correct Answer:
Confused by the solution? Ask the AI to explain a specific step, tell you where you went wrong, or break down the key trap in this question.