Exercise: Head circumference and height, answer 12

Question 12: Would we get a different P value if we carried out the regression of height on head circumference?

Suggested answer

We get a different line, but the P value is the same.

See detailed description at d. d

The regression equation is:

        height = 853 + 1.43 head circumference

This is quite different from the equation

        head circumference = 372 + 0.114 height

which we had earlier. This can be rewritten as

        (head circumference – 372)/0.114 = height

or

        height = –372/0.114 + (1/0.114) head circumference = –3263 + 8.77 head circumference

which is a much steeper line, as shown on the scatter diagram above.

The P value is <0.001, exactly as we had earlier.


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