Final answer:
The second quartile is also known as the median. It is the middle value of an ordered data set, separating the data into two equal halves, and is synonymous with the 50th percentile.
Step-by-step explanation:
The name for the second quartile is median. The median is a central value that divides the data into two equal halves, where half of the values are smaller and half are larger than this central value.
To find the median in a data set, you need to order the data from smallest to largest and then identify the middle value. When this value is located, this represents the second quartile, or 50th percentile.
It's important to note that in a data set with an even number of values, where there is no single middle number, the median is calculated by taking the average of the two middle numbers.
Meanwhile, the first and third quartiles represent the 25th and 75th percentiles respectively, marking the points that separate the data into quarters.