statistics
posted by thelma .
if a data se has a mean of 10.0 seconds & a standard deviation of 2.0 seconds, what is the z score corresponding to the time of 4.0 seconds?

zscore(4s) = (410)/2

Z = (scoremean)/SD
Insert values and calculate. 
A particular statistician knows that approximately 35% of people do not tell the truth when polled. If 400 people were polled in a survey, how many would be expected to answer before someone answers untruthfully?