SOLUTION: The grades of secondary school students on CXC's mathematics examination is normally distributed with a mean of 65% and a standard deviation of 13%. Given this information, 99% of
Algebra.Com
Question 1101737: The grades of secondary school students on CXC's mathematics examination is normally distributed with a mean of 65% and a standard deviation of 13%. Given this information, 99% of students taking the exam score between ___ and ___.
The answer options are :
(a)25% and 75%
(b)52% and 78%
(c)35% and 95%
(d)13% and 65%
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
The grades of secondary school students on CXC's mathematics examination is normally distributed with a mean of 65% and a standard deviation of 13%. Given this information, 99% of students taking the exam score between ___ and ___.
The answer options are :
----
Note: 99% leaves tails of 0.005 or
(1/2)%.
Find the z-value with a left tail of 0.005
z = invNorm(0.005) = -2.5758 for the left tail; +2.5758 for the right tail
---
Find the corresponding percent scores::
x = -2.5758*(0.13) + 0.65 = 0.32 = 32%
x = 2.5758*0.13 + 0.65 = 0.98 = 98%
----------------------
Cheers,
Stan H.
----------------
(a)25% and 75%
(b)52% and 78%
(c)35% and 95%
(d)13% and 65%
RELATED QUESTIONS
The grades of secondary school students on CXC's mathematics examination is normally... (answered by Boreal)
There are 330 students at Valley Central High School enrolled in Chemistry. On the April... (answered by VFBundy)
A set of mid term examination grades in an undergraduate introductory statistics course... (answered by stanbon)
A set of final examination grades in an introductory statistics course was founded to be... (answered by stanbon)
The scores on a college entrance examination are normally distributed with a mean of 550... (answered by VFBundy)
The scores on a college entrance examination are normally distributed with a mean of 550... (answered by Boreal)
The scores on a college entrance examination are normally distributed with a mean of 550... (answered by VFBundy)
A university mathematics department gives a freshman calculus examination that allows... (answered by Boreal)
For a certain mathematics class, the scores are normally distributed with a mean of 75... (answered by Theo)