2 Before leaving for a tour of the UK during the summer of 2008, Eduardo was told that the UK price of a 1.5-litre bottle of spring water was about 50p.
Whilst on his tour, Eduardo noted the prices, \(x\) pence, which he paid for 1.5-litre bottles of spring water from 12 retail outlets.
He then subtracted 50 p from each price and his resulting differences, in pence, were
$$\begin{array} { l l l l l l l l l l l l }
- 18 & - 11 & 1 & 15 & 7 & - 1 & 17 & - 16 & 18 & - 3 & 0 & 9
\end{array}$$
- Calculate the mean and the standard deviation of these differences.
- Hence calculate the mean and the standard deviation of the prices, \(x\) pence, paid by Eduardo.
- Based on an exchange rate of \(€ 1.22\) to \(\pounds 1\), calculate, in euros, the mean and the standard deviation of the prices paid by Eduardo.
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