The idea when using quartiles is take all your data and write it out in increasing order then divide it in 4 equal parts.The upper
quartile is the part containing the highest data values, the upper
middle quartile is the part containing the next-highest data values,
the lower quartile is the part containing the lowest data values,
while the lower middle quartile is the part containing the next-
lowest data values.
Here is the catch-------------- the terms can also refer to cut-off values between the 4 sets.
The term 'upper quartilevcan be
cut-off value between the upper quartile subset and the upper middle
quartile subset. And, the 'lower quartile' can refer to a cut-off value between the lower quartile set
and the lower middle quartile set. usually we look at the interquartile range (IQR) which is the range between the thrird and 1st quartile
IQR is used to make box plots and other cool graphs.
The upper quartile (Q3) is the median of the upper half of the data set. Q3 cuts off highest 25% of data And just FYI: first quartile (designated Q1) = lower quartile = cuts off lowest 25% of data = 25th percentile second quartile (designated Q2) = median = cuts data set in half = 50th percentile
Interquartile Range, or IQR
Consider the data: 1, 2, 2, 3, 4, 4, 5, 7, 11, 13 , 19 (arranged in ascending order) Minimum: 1 Maximum: 19 Range = Maximum - Minimum = 19 - 1 = 18 Median = 4 (the middle value) 1st Quartile/Lower Quartile = 2 (the middle/median of the data below the median which is 4) 3rd Quartile/Upper Quartile = 11 (the middle/median of the data above the median which is 4) InterQuartile Range (IQR) = 3rd Quartile - 1st Quartile = 11 - 2 = 9
In a data sample, the purpose of quartile deviation is a way to measure data dispersion instead of using the range. The quartile deviation is found by subtracting the lower quartile from the upper quartile, and dividing this result by two.
gggggww
Because the IQR excludes values which are lower than the lower quartile as well as the values in the upper quartile.
Interquartile Range, or IQR
The interquartile range of a set of data is the difference between the upper quartile and lower quartile.
The interquartile range :)
There is no need to lose your rag!It is the inter-quartile range.
the range is also known as the IQR or inner quartile range's. The inter quartile range is the difference between the upper quartile and the lower quartile.heresy a good example.Example:18 27 34 52 54 59 61 68 78 82 85 87 91 93 100~First find the median -----> 68~then the lower quartile --> 52~next the upper quartile --> 87after you find these you may subtract the lower quartile (aka UQ) from the upper quartile (aka the UQ)In our case the IQR = 87 - 52 = 35.
Subtract the lower quartile from the upper quartile.
IQR = Inter-Quartile Range = Upper Quartile - Lower Quartile.
It is the upper quartile minus the lower quartile.
The interquartile range (IQR) is a measure of variability, based on dividing a data set into quartiles. Quartiles divide a rank-ordered data set into four equal parts.
The interquartile range is the difference between the Lower quartile and the upper quartile. Obviously you need to be able to find these values. Haylock (2006) explains how to do this for difficult size groups in mathematics explained for primary teachers. He explains the position of the lower quartile is a quarter of (n+1) and that of the upper quartile is three-quarters of (n+1). So for a group of 7 numbers, you find a quarter of 8, which is 2. Therefore the number in second place is the lower quartile. Three quarters of 8 is 6 and so the number in 6th position is the upper quartile. Now take the lower quartile from the upper quartile.
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.
If the result is 1.5 x Inter Quartile Range (or more) above the Upper Quartile or 1.5 x Inter Quartile Range (or more) below the Lower Quartile.