|
Question 757389: On national mathematics tests, the mean is 75, with a standard deviation of 10. The results are very close to fitting a normal curve. Suppose a standard national mathematic test is given to a very large group of people. Find the percentage of people whose mathematics score is:
More than 85
Less than 50
Between 70 and 85
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! On national mathematics tests, the mean is 75, with a standard deviation of 10. The results are very close to fitting a normal curve. Suppose a standard national mathematic test is given to a very large group of people. Find the percentage of people whose mathematics score is:
More than 85
z(85) = (85-75)/10 = 1
P(x > 85) = P(z > 1) = 0.1587
-----------------------------
Less than 50
Find the z-value of 50
Find the probability z is greater than that z-value.
------------------------------
Between 70 and 85
Find the 2 z-values
Find the probability that z is between those z-values.
================================
Cheers,
Stan H.
==================
|
|
|
| |
