Quote:
Originally Posted by gmacaree
Am having exactly the same issue  I was using a lazy pointfitting technique and came up with an answer matching one of the choices, but then as soon as I used a more rigourous solution for throughtheorigin regression I end up with a slope of 1.42. That's obviously incorrect but I'm slightly baffled as to why I get it right when I do it wrong and wrong when I do it right!

Same here. I used the linear regressionthroughtheorigin formula and came up with a slope of
. The first time I just used the slope from the line that passes through both points, and got
.
What makes you say that
is obviously incorrect though?