Question

If \(X\) is a normal random variable with mean \(\mu=100\) and variance \(\sigma^2=25\), then \[ P(90<X<120) \] is same as ____.

• A. \(P(-1<Z<1)\)
• B. \(P(-2<Z<4)\)
• C. \(P(4<Z<4.1)\)
• D. \(P(-2<Z<3)\)

Hint:

To standardize a normal random variable, \[ \boxed{ Z=\frac{X-\mu}{\sigma} } \] where \[ \mu=\text{Mean},\qquad \sigma=\text{Standard deviation}. \]

Answer 1

The Correct Option is B