Finding the value of chi-squared for a linear fit

How do you use matlab to derive a formula for making a linear fit to data with an intercept at the origin so that y=bx and then apply it to your model to fit a straight line through the origin to the data given below

Assume uniform uncertainties σi= 1.5 in yi

The how do you find the value of chi-squared for the fit?

and the uncertainties in b and R^2.

Data:

xi= 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24

yi= 5.3, 14.4, 20.7, 30.1, 35.0, 41.3, 52.7, 55.7, 63.0, 72.1, 80.5, 87.9

Answer 1

[dpb]

mdl=fitlm(xi,yi,'intercept',false);