:2. Solution. We need the EV and SE of the average of 100
draws from the box. To find these, we first get the EV and SE of
the sum of 100 draws. The box average is 100, so the EV of the
sum of the draws is 100 x 100 = 10,000. The box SD is 20, so the
SE of the sum of the draws is 10 x 20 = 200. To find the
corresponding quantities for the average of the draws, we divide
each by the number of draws. The EV of the average of the draws
is 10,000/100 = 100. The SE of the average of the draws is
200/100 = 2. Since
(98 - 100)/2 = -2/2 = -1 and (102 - 100)/2 = 2/2 = 1 ,

The chance that the average of the 100 tickets in the sample is
between 98 and 102 is approximately equal to the area under the
normal curve between -1 and 1, which is 68%.