Statistics

Board: CBSE Class: 10

Chapter Overview

Statistics involves collecting, organizing, and interpreting numerical data. For grouped data, the mean can be found by the direct method, assumed mean method, or step deviation method. The median of grouped data is found using the formula: median = l + ((n/2-cf)/f) x h, where l is the lower limit of the median class. The mode of grouped data is found using: mode = l + ((f1-f0)/(2f1-f0-f2)) x h. Graphical representations include cumulative frequency curves (ogives).

Topics Covered

Grouped Data
Direct Mean Method
Assumed Mean Method
Step Deviation Method
Median of Grouped Data
Mode of Grouped Data
Cumulative Frequency
Ogive Curves

Key Formulas

Mean (direct) = sum fixi/sum fi

Mean (step deviation) = a + (sum fidi/sum fi) x h

Median = l + ((n/2-cf)/f) x h

Mode = l + ((f1-f0)/(2f1-f0-f2)) x h

Real-World Applications

Applications: Data analysis, survey results, business analytics, economic indicators, quality control.

Study Tips

Tip: Practice all three methods of finding mean

Tip: Learn median formula with correct notation

Tip: Draw ogive curves carefully