Lifetime of a TV is normally distributed with mean = 6 years and s.d. = 2 years. If no more than 5% is to be replaced in the warranty period, what should be the maximum number of years for the warranty period? ( Answer correct to 1 d.p.)
Correction : Should be corrected to the nearest year, not to 1 d.p.
- 自由自在Lv 79 年 前最佳解答
Pr(z < Z) = 5% => z = –1.64z = (x – 6) / 2 = –1.64 => x = 2.72Hence the maximum number of years for the warranty period should be 2