SOLUTION: the marks for test 1 for a particular subject are normally distributed with a mean of 52 marks and variance 26. a student was selected from class. what is the probability that this

Algebra ->  Probability-and-statistics -> SOLUTION: the marks for test 1 for a particular subject are normally distributed with a mean of 52 marks and variance 26. a student was selected from class. what is the probability that this      Log On


   

Question 758437: the marks for test 1 for a particular subject are normally distributed with a mean of 52 marks and variance 26. a student was selected from class. what is the probability that this student obtained
(i)at least 60 marks in test1
(ii) it was told that 5% of the student obtained at least x marks in test 1.calculated the value x
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
the probabiity that a student picked at random from the class had a score greater than or equal to 60 marks is .2164.
see the following picture from the normal distribution calculator that i used.

$$$$$

the score that 5% of the students obtained or got greater than is equal to 64.389.

see the following picture from the normal distribution calculator that i used.

$$$$$

this calculator can be found at the following link:

http://davidmlane.com/normal.html

you need to calculate the standard deviation which is the square root of the variance.