First Quartile Meaning. The value of the variable below which one quarter of the elements are located. May 17 2016 The first quartile denoted Q 1 is the value in the data set that holds 25 of the values below it.
Similar to how the median denotes the midway point of a data set the first quartile marks the quarter or 25 point. For achievement and proficiency tests the first quartile is the place to be. It is the median of any data set and it divides an ordered data set into upper and lower halves.
The third quartile Q 3 is the 75th percentile.
In the topsecond etc. The value of the variable below which one quarter of the elements are located. Examples Dataset size divisible by. Since half of the data is less than the median and one-half is equal to 50 percent the median marks the 50th percentile.
