first quartile (Q1) : Total number of term(N)/4 = Nth term third quartile (Q3): 3 x (N)/4th term
Third quartile
83
41
21
The first quartile, or the lower quartile, is the value such that a quarter of the observations are smaller and three quarters are larger.The third quartile, or the upper quartile, is the value such that three quarters of the observations are smaller and a quarter are larger.
the IQR is the third quartile minus the first quartile.
Roughly speaking, finding the third quartile is similar to finding the median. First, use the median to split the data set into two equal halves. Then the third quartile is the median of the upper half. Similarly, the first quartile is the median of the lower half.
50%
first quartile (Q1) : Total number of term(N)/4 = Nth term third quartile (Q3): 3 x (N)/4th term
Third quartile
75th percentile
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.
First Quartile = 43 Third Qaurtile = 61
The value of any element in the third quartile will be greater than the value of any element in the first quartile. But both quartiles will have exactly the same number of elements in them: 250.
interquartile range or IQR
83