The heights, \(x\) cm, of a group of 28 people were measured. The mean height was found to be 172.6 cm and the standard deviation was found to be 4.58 cm. A person whose height was 161.8 cm left the group. (i) Find the mean height of the remaining group of 27 people. (ii) Find \(\Sigma x^2\) for the original group of 28 people. Hence find the standard deviation of the heights of the remaining group of 27 people.