n = 5148 ps = 5041 (71) ns = 5184 (72) sqrt(5148) ~ sqrt(5041) + 5148-5041/(5184-5041-1+1/(5184-5041-1)) sqrt(5148) ~ 71 + 107/(143+1/143) sqrt(5148) ~ 71 + 107*0.00699 sqrt(5148) ~ 71 + 0.748 sqrt(5148) ~ 71.74821 sqrt(5148) =~ (real) 71.74956 71.74956-71.74821 = 0.00135 or 0.188% error