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Find Q1 Q2 and Q3 using this free online quartiles calculator.
What is the First, Second and Third Quartile
The first quartile marks the point that is bigger than 25% of all data.
The second quartile represent the median which is bigger than 50% of all data.
The third quartile represents ther number that is higher than 75% of all data
What is interquartile range IQR
Interquartile range is the difference between Q1 and Q3. It can be calculated as Q3 - Q1. The IQR is always positive because Q3 is always greater than or equal to Q1.
What Does the IQR tell you
A large interquartile range means that the middle of the distribution of your numbers is quite spread out. if you plot the data as a histogram the middle Peaks would not be very high and instead would be kind of flat.
A small interquartile range means that the middle part of your data is congested. If you plotted your data as a histogram the middle bins would be very high.
How Do You Calculate Q1, Q2 and Q3
Order your data from lowest number to highest
Find the number that is bigger than 25% of all other numbers. This is Q1.
Find the number that is bigger than 50% of all numbers. This is Q2, aka the median.
Find the number that is bigger than 75% of all numbers. This is Q3.