The true length of boards cut at a mill with a listed length of 10 feet is normally distributed with a mean of 123 inches and a standard deviation of 1 inch. What proportion of the boards will be between 121 and 124 inches?
选项:
A:0.3116;
B:0.3186;
C:0.9186;
D:0.8186
发布时间:2024-04-08 09:17:34