SOLUTION: Suppose that, for a certain exam, a teacher grades on a curve. It is known that the mean is 65 and the standard deviation is 10. There are 45 students in the class. What sc

Algebra ->  Probability-and-statistics -> SOLUTION: Suppose that, for a certain exam, a teacher grades on a curve. It is known that the mean is 65 and the standard deviation is 10. There are 45 students in the class. What sc      Log On


   

Question 1201050: Suppose that, for a certain exam, a teacher grades on a curve.

It is known that the mean is 65 and the standard deviation is 10. There are 45 students in the class.
What score would be necessary to obtain an A?
99
Found 2 solutions by Theo, ikleyn:
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
the mean is 65
the standard deviation is 10
the class size is 45.
you would need to know what percent of the class fall into each category.
assuming the distribution is normal, and assuming that 2% of the class are assumed to get an A, then you would look for what score is required to be in the top 2% of the class, grade wise.
using the normal distribution calculator at https://davidmlane.com/hyperstat/z_table.html, it looks like the grade that would be required to get an A in this class would be a score greater than 85.
here are the results from using that calculator.






Answer by ikleyn(52794) About Me  (Show Source):
You can put this solution on YOUR website!
.

The problem is posed INCORRECTLY.

As posed, it can not be solved, at all.

To be solved, the problem should be modified.