# Graph description: Figure 13. BMI and abdominal circumference, showing the simple linear regression line and the quadratic curved line

This graph shows a scatter diagram.

The horizontal axis shows abdominal circumference in centimetres and is numbered 40, 60, 80, 100, 120. The vertical axis shows body mass index in kilogrammes per square metre and is numbered 10, 20, 30, and 40.

There is a fairly strong relationhsip about a straight line from abdominal circumference = 40, body mass index = 11 to abdominal circumference = 120, body mass index = 36. The cloud of points lies between body mass index = 10 and 20 when abdominal circumference = 50, to between body mass index = 30 and 40 when abdominal circumference = 110. In the centre of the cloud the straight line appears to be nearer the top than the bottom of the cloud of points and at the lower end to be nearer to the bottom of the cloud, but these effects are quite small.

There is also a curved line, which starts above the straight line at abdominal circumference = 40, body mass index = 15, rises but not as steeply as the straight line to cross it at abdominal circumference = 68, becomes more steep to cross the straight line again at abdominal circumference = 88, and finishes above the straight line at abdominal circumference = 120, body mass index = 40.

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