# Homework Help: Statistic maths

1. Jul 16, 2010

### jinx007

Please try this question and see whether you got my answer...i am having some doubt

The random variable X is normally distributed with mean V and variance C^2. It is known that P(x>102)=0.42 and P(x<97)=0.25

calculate V(mean) and variance c^2

i got mean 100.8 and variance(-5.7)^2

2. Jul 16, 2010

You need to show some work, but one comment: if you say the variance is $(-5.7)^2$, you are implicitly saying the standard deviation is $-5.7$, which is impossible.