Question
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.
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.
Answers
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 ????
and since nobody "deviated" from that score, wouldn't the standard deviation be zero ????
Anonymous
Suppose the scores of students on an exam are normally distributed with a mean of 507 and a standard deviation of 97. According to the empirical rule, what percentage of students scored between 410 and 604 on the exam?