The mean of the frequency distribution is 46.9 miles per hour.
The computed mean to the actual mean of 46.5 miles per hour.
Lest find the 5% of 46.9
(46.9 * 5)/100 = 2.3
The real difference 46.9 - 46.5 = 0.4
The computed mean is close to the actual mean because the difference between the means is less than 5%.