Chrystal is studying the lengths of pine cones that have fallen from a tree. She believes that the length, $$\(X \mathrm{~cm}\)$$, of the pine cones can be modelled by a normal distribution with mean $$\(6 \mathrm{~cm}\)$$ and standard deviation $$\(0.75 \mathrm{~cm}\)$$. She collects a random sample of 80 pine cones and their lengths are recorded in the table below. Using a 10\% level of significance, complete David's test stating the critical value and the degrees of freedom used. (3)

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