Question 587095: Two students take a college entrance exam known to have a normal distribution of scores. The students receive raw scores of 74 and 94, which correspond to z scores (often called the standardized scores) of -1 and 2.0, respectively. Find the mean and standard deviation of the distribution of raw exam scores. (Use five decimal places in the intermediate calculations. Round your final answers to 4 decimal places.)
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Two students take a college entrance exam known to have a normal distribution of scores. The students receive raw scores of 74 and 94, which correspond to z scores (often called the standardized scores) of -1 and 2.0, respectively. Find the mean and standard deviation of the distribution of raw exam scores. (Use five decimal places in the intermediate calculations. Round your final answers to 4 decimal places.)
-----
Use the form x = z*s + u
74 = -1s + u
94 = 2s + u
------
Subtract and solve for "s":
3s = 20
s = 20/3
--------
Solve for "u":
74 = (-20/3) + u
u = 222/3 + 20/3
----
u = 242/3 = 80 2/3
========================
Cheers,
Stan H.
========================
|
|
|
