Finding Normal probability distribution

Question

The weight of a newborn baby is believe to have a normal distribution with mean of weight of 3915 and variance of 429,025. If one baby is randomly selected what is the probability that the weight will be less than 4570 grams

Answer 1

The standard deviation is the square root of variance, thus σ = 655.

 

The value 4570 grams is μ+σ, i.e. you want P(Z<1)...and that should be easy for you, now.  Answer is about 84%