Normal Distribution
Also known as the Gaussian Distribution, the Normal Distribution is widely used to model a variety of events of a random nature.
The graph of a Normal Distribution is known as the bell curve because of its resemblance to a bell-shaped figure.
The calculations involved in finding the area under the bell curve are too complex for a person with the mathematics tools like algebra and even calculus.
That is why there are special resources that give us the accumulated area of the normal distribution, from tables to online calculators.
We frequently use MS Excel which has a special function called NORMDIST that computes the area under the curve for the left tail where a variable called z-score is given.
We are required to find the area for z between 0 and 1.96, that is 0 < z < 1.96
First, we find the area for z = 1.96. Result: 0.975
Now we find the area for z = 0. Result: 0.5
The required area is: 0.975 - 0.5 = 0.475
Answer: D 0.475