Page 2: Ratios and Data Analysis
This page delves into ratios and data analysis techniques, essential components of the Programme maths 3ème.
The concept of ratios is explained, showing how to express relationships between numbers and divide quantities proportionally.
Example: To share 240€ between two people in the ratio 2:3, divide 240 by (2+3)=5, then multiply by respective ratio parts: 48x2=96€ and 48x3=144€.
Data analysis techniques are introduced, including measures of central tendency and spread.
Definition: Mean (moyenne) is calculated as the sum of all values divided by the number of values.
Vocabulary: Median (médiane), quartiles, range (étendue).
The page also covers the calculation of median and quartiles, which are important for understanding data distribution.
Highlight: Quartiles divide ordered data into four equal parts, with Q1 at 25% and Q3 at 75% of the data.
Weighted average is briefly mentioned, showing how to account for different weights of data points.
Example: Weighted average = (ax1 + bx2 + cx2 + dx3) / (1 + 2 + 2 + 3)
These concepts are crucial for exercices corrigés in data analysis for 3ème students.