Mathematics for IGCSE & O level - Statistical Diagrams (Section 2 - No. 15)
How is the lower quartile estimated using a cumulative frequency diagram?
The value on the x-axis corresponding to the 25th percentile.
The value on the y-axis corresponding to the 25th percentile.
The x value when the cumulative frequency reaches its maximum
The median is doubled.
Explanation
The lower quartile is estimated by finding the x-axis value at the 25th percentile on the y-axis.