A battery company claims that its batteries last an average of 100 hours under normal use. There have been several complaints that the batteries don't last that long, so an independent testing agenty is engaged to test them. For a random sample of 16 batteries they tested, the sample mean life time was 90-hours and the sample standard deviation was 20 hours. The calculated value of the t-statistic is: O-0.459 O -0.606 O 0.8 O -0.8