:11. A box is known to have a histogram which follows the
normal curve. The box SD is equal to 10. The null hypothesis
says that the box average is 0. The alternative hypothesis says
that the box average is 20. One ticket is drawn at random from
the box. The number on it is 15. Letting
z = (observed - expected)/SE ,

the observed significance level is closest to

a. 2.5%
b. 7%
c. 16%
d. 50%
e. can't be computed