The following data resulted from 15 independent measurements of the melting point of lead. 322.3 339.1 323.3 330.8 328.4 323.2 3
38.3 324.2 334.9 328.2 329.4 329.5 328.2 339.7 326.5 Assuming that the measurements can be regarded as constituting a normal sample whose mean is the true melting point of lead, determine a 95% confidence interval for this value.