Posted by Tiffany on .
Suppose every student in your class got a score of 85% on an exam. What are the mean and standard deviation of those exam scores without doing any calculations?
I want to say the mean is 100 and the standard deviation is 1 but I don't know why. If all students scored 85% that would be 100% of them so that's how I got 100 but I don't understand how to reach the standard deviation.

probability and statistics 
Reiny,
Ummmh, if everybody got an 85, wouldn't the average be 85 ??? , so mean = 85
and since nobody "deviated" from that score, wouldn't the standard deviation be zero ????