In: Statistics and Probability
Suppose that X is normally distributed with a mean of 50 and a standard deviation of 12. What is P(X ≥ 74.96)
a) 0.481
b) 0.019
c) 0.981
d) 0.024
e) 0.020
f) None of the above
Solution:
Given: X is normally distributed with a mean of 50 and a standard deviation of 12.
That is: X ~ Normal
We have to find: =........?
Find z score:
thus we get:
Look in z table for z = 2.0 and 0.08 and find area.
P( Z< 2.08)= 0.9812
Thus
( Rounded to 3 decimal places.)
Thus correct option is b) 0.019