In order to test the precision of a new type of blood sugar monitor for diabetic patients, 20 randomly selected monitors of this type were used. A blood sample with 120 mg/dL was tested in each of these monitors, and the resulting readings are given in the following table.

(a) Obtain a 99% confidence interval for the variance σ2.
(b) Is it reasonable to assume that the data follow a normal distribution?

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117 116 12 120 122 117 120 120 118 119 118 123 119 123 119 122 8 122 121 120