29. The amount of shaft wear (.0001 in.) after a fixed mileage was determined for each of n
8 internal combustion engines having copper lead as a bearing material, resulting in x

3.72 and s
1.25.

a. Assuming that the distribution of shaft wear is normal with mean , use the t test at level .05 to test H0:

3.50 versus Ha: 3.50.

b. Using
1.25, what is the type II error probability

( ) of the test for the alternative
4.00?