# Question

A new purification unit is installed in a chemical process. Before its installation, a random sample yielded the following data about the percentage of impurity: x12 9.85,s12 6.79 and n1 10 . After installation, a random sample resulted in x22 8.08,s22 6.18 and n2 8.

(a) Can you conclude that the two variances are equal? Use =0.05.

(b) Can you conclude that the new purification device has reduced the mean percentage of impurity? Use a = 0.05.

(a) Can you conclude that the two variances are equal? Use =0.05.

(b) Can you conclude that the new purification device has reduced the mean percentage of impurity? Use a = 0.05.

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