Hi all, Im a bit confused on the serial correlations test. I undertsand the formula and am able to obtain the denominator, but the right bracket (Z_x+1-averageZ_x) on the numerator has confused me. For example, graduation B in chapter 10 goes from x=30 to x=49, so say when i get to x=49, then ofcourse x+1=50 which we don't have a z_x for. So in this case would the numerator be (Z_49-average z_X)(0-averageZ_X)? im not sure how i would go about finding the numerator value for this value of x? please can someone help? Thanks!
Hello The summation of the terms in the numerator go up to m-j when testing at lag j. It looks like you're considering the case when j = 1, in which case the final term will be when x is 48. Hope this helps! Andy
