2 A rowing club has a large number of members.A random sample of 12 of these members is taken and the pulse rate,\(x\) beats per minute(bpm),of each is measured after a 30 -minute training session.A \(98 \%\) confidence interval for the population mean pulse rate,\(\mu \mathrm { bpm }\) ,is calculated from the sample as \(64.22 < \mu < 68.66\) .

1. Find the values of \(\sum x\) and \(\sum x ^ { 2 }\) .
2. State an assumption that is necessary for the confidence interval to be valid.
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