The heights, in metres, of a random sample of 8 trees of a particular type are as follows.
\[\begin{array}{llllllll}
14.2 & 11.3 & 10.8 & 8.4 & 12.8 & 11.5 & 12.1 & 9.2
\end{array}\]

Assuming that heights of trees of this type are normally distributed, calculate a 95\% confidence interval for the mean height of trees of this type.