SOLUTION: If X is a normal random variable with standard deviation 3.50, and if the probability that X is more than 12.33 is .1271, then what is the mean of X?
Algebra ->
Probability-and-statistics
-> SOLUTION: If X is a normal random variable with standard deviation 3.50, and if the probability that X is more than 12.33 is .1271, then what is the mean of X?
Log On
Question 630356: If X is a normal random variable with standard deviation 3.50, and if the probability that X is more than 12.33 is .1271, then what is the mean of X? Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! If X is a normal random variable with standard deviation 3.50, and if the probability that X is more than 12.33 is .1271, then what is the mean of X?
----
P(x > 12.33) = 0.1271
---
Find the z-value with a right tail of 0.1271
invNorm(1-0.1271) = 1.1402
---
Use z = (x-u)/s to find u.
---
1.1402 = (12.33-u)/3.50
-u = (1.1402*3.50) - 12.33
-u = -8.3393
----
u = 8.3393
==========================
Cheers,
Stan H.
===============
(