A quartile divides a grouping into four. The first quartile will have the first 25% of the group, the second quartile will have the second 25% of the group, the third quartile will have the third 25% of the group and the last quartile will have the last 25% of the group. For example if a classroom had 20 students who had all taken a test, you could line them up, the top 5 marks would be in the first quartile, the next five would be in the second quartile, the next 5 would be in the third quartile, and the 5 students with the lowest marks would be in the last quartile. Similarly, a percentile divides a grouping, except the group is divided into 100. Each 1% represent 1 percentile.
If a set of data are ordered by size, then the lower quartile is a value such that a quarter of the data are smaller than it. The upper quartile is a value such that a quarter of the data are larger than it. Interquartile means between the quartiles.
3rd quartile = 75th percentile and so is "better".
Interquartile range.
Find the difference between the values for quartile 3 and quartile 1.
lower quartile
75th percentile
Median = 50th percentile or 2nd quartile or 5th decile.
If a set of data are ordered by size, then the lower quartile is a value such that a quarter of the data are smaller than it. The upper quartile is a value such that a quarter of the data are larger than it. Interquartile means between the quartiles.
3rd quartile = 75th percentile and so is "better".
Third quartile
Interquartile range.
Interquartile Range, or IQR
Find the difference between the values for quartile 3 and quartile 1.
The quartile deviation(QD) is half the difference between the highest and lower quartile in a distribution.
Find the difference between the values for quartile 3 and quartile 1.
lower quartile
interquartile range or IQR