right okay can you go into the, just log the data    okay last week we were looking at test for structural change and we said that the chow test is the most commonly used test for structural change  in actual fact chow developed two tests erm, the parameter constancy, i e structural change,fir the first one is where you remember what the, the principle behind the chow test that you split the whole sample into two sub periods, right and you see whether the, some of the res residual sum of squares from each sub sample, right, is significantly different from the residual sum of squares from a single estimation over the who whole sample period, right  if they are significantly different that suggests that the parameters that are estimated over the full er sample period, right, aren't as good estimates as the unrestricted estimates when we are allowing two different sets of parameters just to be estimated.