Question

Basic Computation: Finding Probabilities, let z be a random variable with a standard normal distribution. Find the indicated probability, and shade the corresponding area under the standard normal curve.

P(-1.20 = z = 2.64)

Answer 1

0.8808

Explanation:

The objective is to calculate the probability of:

P(-1.20 ≤ z ≤ 2.64)

i.e. the probability that is the area between two z-values.

Thus;

P(-1.20 ≤ z ≤ 2.64) = P(z ≤ 2.64) - P( z ≤ 1.20)

From z table;

P(-1.20 ≤ z ≤ 2.64) = 0.9959 - 0.1151

P(-1.20 ≤ z ≤ 2.64) = 0.8808

We can see the shaded area under the standard normal curve from the image attached below.