Speed data were collected at a section of highway during and after utility maintenance work. The speed characteristics are given below. Determine whether there was any significant difference between the average speeds at the 95% confidence level.

overline $u_1$= 35.3mph	$u_2=38.7mph$
$S_1$ = 7.5mph	$S_2=7.4mph$
$n_1=250$	$n_2=280$