A random sample of 9 members is taken from the large number of members of a sports club, and their heights are measured. The heights of all the members of the club are assumed to be normally distributed. A 95\% confidence interval for the population mean height, \(\mu\) metres, is calculated from the data as \(1.65 \leqslant \mu \leqslant 1.85\).
(i) Find an unbiased estimate for the population variance.

(ii) Denoting the height of a member of the club by \(x\) metres, find \(\Sigma x^{2}\) for this sample of 9 members.