A new spectrophotometer is being calibrated It is not clear

A new spectrophotometer is being calibrated. It is not clear whether the errors follow the normal curve, or even whether the Gauss model applies. In two cases, these assumptions should be rejected. Which two, and why? The numbers are replicate measurements on span gas. (a) 71, 70, 72, 69, 71, 68, 93, 75, 68, 61, 74, 67 (b) 71, 73, 69, 74, 65, 67, 71, 69, 70, 75, 71, 68 (c) 71, 69, 71, 69, 71, 69, 71, 69, 71, 69, 71, 69

Solution

Find mean and std dev for the sample

a) Mean = 74.08 std dev=8.34

b) Mean = 70.25, std dev = 7.69

c) Mean =70 std dev = 1.04

Of the above 3, we find that a has an outlier of 93. and c has repitition of probabilities

Hence a and c can be rejected.