A company manufacturing stereo equipment claims that their personal CD player can be used for approximately 8 hours of continuous play when used with alkaline batteries. To provide this estimate, the company tested 35 CD players with new alkaline batteries and recorded the time at which the batteries in the players lost power. The average time was 8.3 hours with a sample standard deviation of 1.2 hours.

1. Construct a 98% confidence interval for the mean time until a new alkaline battery used in the CD player loses power.

CI = _____________________________

2. Determine the required sample size in order to estimate the mean time until a new alkaline battery used in the CD player loses power to within 10 minutes at the 99% confidence level.

______________________________