A scatter diagram.

The horizontal axis is labeled "Age in years" and numbered 20, 30, 40, 50, 60, and 70. The vertical axis is labeled "Muscle strength in newtons" and numbered 100, 200, 300, 400, and 500. Each of the 41 subjects is shown by a small circle positioned at that person's age and strength.

Older men tend to have less strength, but the relationship is not close. For age = 30, strength ranges from 150 to 500. For age = 60, strength ranges from 80 to 200.

There is a horizontal line through strength = 320, labeled "Mean strength". There is a vertical line through age = 41, labeled "Mean age". The top left quadrant is labeled "negative". The top right quadrant is labeled "positive". The bottom left quadrant is labeled "positive". The bottom right quadrant is labeled "negative".

The majority of observations are in the top left and bottom right quadrants.

Back to Clinical Biostatistics: Correlation.

This page maintained by Martin Bland.

Last updated: 30 August, 2006.