Question

You may need to use the appropriate appendix table or technology to answer this question. z is a standard normal random variable. Find P(1.8≤z≤2.1).

a. 0.0181
b. 0.9641
c. 0.9819
d. 0.9821

Answer 1

To find the probability P(1.8 ≤ z ≤ 2.1), subtract the area to the left of 1.8 from the area to the left of 2.1 on the z-table.

Step-by-step explanation:

To find the probability P(1.8 ≤ z ≤ 2.1), we need to calculate the area under the standard normal curve between these two z-scores.

The z-table shows that the area to the left of 1.8 is 0.9641 and the area to the left of 2.1 is 0.9819. To find the area between these two z-scores, we subtract the smaller area from the larger area: 0.9819 - 0.9641 = 0.0178.

Therefore, the probability P(1.8 ≤ z ≤ 2.1) is approximately 0.0178.