A chemist acquired the following data for the alcohol content of blood: %C2 H5OH: 0.084, 0.098 and 0.079. Determine the 95% confidence interval for the mean assuming
a) the three results acquired are the only indication of the precision of the method and
b) we know that the sample standard deviation,s, is 0.005% and is a good estimate of the true standard deviation, σ from previous experience on hundreds of samples.