Watch Corporation of Switzerland claims that its watches on

Watch Corporation of Switzerland claims that its watches on average will neither gain nor lose time during a week. A sample of 18 watches provided the following gains (+) or losses (-) in seconds per week. -.30 -.20 .00 -.32 .20 -.23 .00 .25 -.10 -.37 -.61 -.30 .40 -.64 .00 .10 -.68 .30

(a-1) Is it reasonable to conclude that the mean gain or loss in time for the watches is 0? Use the .01 significance level. At a level of .01 significance, we reject H0: ? = 0 if t___ < or t >___ . (Negative amounts should be indicated by a minus sign. Round your answers to 3 decimal places.)

(a-2) The value of the test statistic is . (Negative amount should be indicated by a minus sign. Round your answer to 2 decimal places.)

Solution

a1) -2.898 and 2.898

a2)  -1.82