A particular brand of diet margarine was analyzed to determine the level of polyunsaturated fatty acid (in percentages). A sample of six packages resulted in the following data: 16.8, 17.2, 17.4, 16.9, 16.5, 17.1.
(a) Is there evidence to support the assumption that the level of polyunsaturated fatty acid is normally distributed?
(b) Find a 99% confidence interval on the mean μ. Provide a practical interpretation of this interval.