A s a m p le o f 2 0 p a ired o b s e r v a tio n s g e n e r a t e s t h e f o llo w in g data: A s s u m e a normal distribution.

a. Construct a 90% confidence interval for the mean difference μD.

b. Using the confidence interval, test whether the mean difference differs from zero. Explain. PG-69