Question

A normal distribution has μ = 80 and σ = 10. What is the probability of randomly selecting between the mean and a score of 90

Answer 1

$P(80<X<90)=P(\frac{80-80}{10}<Z<\frac{90-80}{10})=P(0<Z<1)=$

$=P(Z<1)-P(Z<0)=0.8413-0.5=0.3413.$