Question
If there are 1000 people in a group, how many would you expect to score above 90?
Mean: 85
SD: 10
Mean: 85
SD: 10
Answers
Reiny
go to
http://davidmlane.com/hyperstat/z_table.html
enter 85 for the mean, 10 for the SD
click on above and enter 90 in that box
read : 0.308538 in the "shaded" part
so expected number above 90 from 1000 people is
.308538(1000) = 308.5 , so appr. 309 people
http://davidmlane.com/hyperstat/z_table.html
enter 85 for the mean, 10 for the SD
click on above and enter 90 in that box
read : 0.308538 in the "shaded" part
so expected number above 90 from 1000 people is
.308538(1000) = 308.5 , so appr. 309 people