One way would be to compute the 95% confidence interval of the regression coefficients and determine whether they overlap (which would confirm the null hypothesis). If and only if your data do not have significant outliers, you can use the coefCI function which assumes an approximately normal distribution of error.
% mdl is the linear regression model
% CI is an nx2 matrix of [low,high] CI endpoints for each n coefficient
ci = coefCI(mdl)
