Each (hypothetical) data set below represents some readings on span gas. Assume the Gauss model, with errors following the norma
l curve. However, bias may be present. In each case, make a t-test to see whether the instrument is properly calibrated or not. In one case, this is impossible. Which one, and why? a. 71, 68, 79
b. 71, 68, 79, 84, 78, 85, 69
c. 71
d. 71, 84
