Question

Consider a normal distribution with mean 21 and standard deviation 4. What is the probability a value selected at random from this distribution is greater than 21

Answer 1

P [ Z > 21 ] = 0,5 or P [ Z > 21 ] = 50 %

Explanation:

Normal Distribution N(21;4)

The question here is what is the area of the bell shape curve. As 21 is a mean for this distribution is in the middle of the bell, so values bigger than 21 will have a probability of 0,5, and values smaller than 21 will have the same probability 0,5. We must remember that the whole area under the curve has an area of 1 ( or 100% )