you have a digital clock ( no seconds ) that you randomly look
at once at a time defined as t1 and then keep looking until
it turns to the next minute defined as t2.
a) what is the expected value of t2-t1 ( i.e : mu ) and variance of
t2-t1 ( i.e :sigma squared )
b) what is mu plus or minus 2*sigma and what does it mean ?
理解为t1和t2是两个独立的U[0,60]吗?还是别的?b是说confidence interval吗?谢
谢。