Final answer:
To find a z-score with 0.21 area to its right, subtract 0.21 from 1, locate 0.79 in a Z-table, and identify the corresponding z-score, which is approximately 0.81.
Step-by-step explanation:
The question involves using the Q Cumulative Normal Distribution Table (or Z-table) to find a specific z-score which corresponds to a given area under the standard normal curve. In this case, we are looking for the z-score that has an area of 0.21 to its right. Since most Z-tables provide the area to the left of the z-score, you would need to subtract the given area from 1 to find the corresponding area to the left. For example, 1 - 0.21 = 0.79. Now, you search the Z-table for the area that is closest to 0.79, which would yield a z-score that has 0.21 area to the right of it.
When you find the area of 0.79 in the Z-table, you will actually find a z-score that is approximately 0.81. Since Z-tables typically round areas to four decimal places, it may not be a perfect match, but 0.81 is the z-score that corresponds to an area of approximately 0.79 to the left, meaning it has approximately 0.21 area to its right.