To find the third quartile, or Q3, we need to first arrange the data set in numerical order. This would give us: 18, 18, 18, 19, 20, 21, 23, 25, 30 To find Q3, we need to first find the median, or middle value, of the data set. We do this by dividing the number of values in the set by 2. In this case, we have 9 values, so the median would be the value at the 9/2 = 4.5th position. Since we can't have a half value, we need to take the average of the two values that surround this position, which are the values at the 4th and 5th positions. In this case, these values are 19 and 20, so the median would be (19 + 20) / 2 = 19.5. Now that we know the median, we can find the third quartile by finding the median of the values that are greater than the overall median. In this case, we have the values 21, 23, 25, and 30. The median of these values is (23 + 25) / 2 = 24, so Q3 is 24. Therefore, the third quartile, or Q3, of the data set is 24. Answer from mrwho2019 on reddit.com
EDUCBA
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Quartile Formula in Statistics: Examples, Interquartile Range, Template
September 20, 2023 - In simple terms, the quartile formula is an advanced version of the median formula. Similar to how the median gives us one middle value for a set of data by dividing the entire data into 2 equal parts, quartiles give us three middle values by dividing a set of data into four equal parts. Quartiles are a useful statistical tool that helps statisticians study a set of data and understand the arrangement of data in a dataset.
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Quartile Formula with Solved Examples
July 8, 2022 - Get answers to the most common queries related to the Quartile Formula. Ans. It is implemented to divide a data set into four equivalent parts.
Calculating quartile
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December 6, 2022Quartiles | Formula, Definition and Solved Examples
Quartiles divide a data set into four equal parts, each containing 25% of the data. They help to understand the spread and center of the data. As an important concept in statistics, quartiles are used to analyze large data sets by highlighting values near the middle. More on geeksforgeeks.org
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[Basic Statistics] Why isn't the median included in quartile calculations?
But why isn't the first quartile 5 instead of 4.5? But ... but, you do it on the sorted data. 4 5 3 2 3 -> 2 3 3 4 5 2 3 3 4 5 Q1 Med Q3 Actually, in many definitions of sample quartiles, the lower quartile IS the second observation. In R, for example, there are nine definitions of quantiles in the "quantile" function (implying nine ways of arriving at a lower quartile), plus the lower hinge in the five number summary (and in the boxplot). Of those ten possible 'quartile' definitions in R, four of them give the second observation when n=5. Only one of the ten gives the (n+1)/4th observation Don't assume some site on the internet is the last word on anything. More on reddit.com
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August 17, 2014[Question] How do I understand Quartiles? What information do I need to find them?
So every time I try to find the Q1 and Q3 pieces of data I always get it wrong Note that there's at least 9 different definitions used in stats packages, and a few more across the range of available textbooks. That's not even counting the definition of hinges (which are used in Tukey's definition of box plots). Is there a specific formula I am meant to use No doubt there is, but we can't guess which one it might be - it depends on who is deciding what the required answer should be. If you have notes or a textbook, you should probably be using its definition. If you can find the IQR correctly, then the two numbers you subtracted to get it should be the first and third quartiles. More on reddit.com
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June 2, 2022What is the purpose of the quartile formula?
Ans. It is implemented to divide a data set into four equivalent parts.
unacademy.com
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Quartile Formula with Solved Examples
What is the formula for the interquartile range?
Ans. Interquartile range or IQR is measured by evaluating the difference between the third quartile and first quarti...Read full
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Quartile Formula with Solved Examples
How do I find the quartiles of a probability distribution?
To find the quartiles of a probability distribution, you can use the distribution’s quantile function.
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Quartiles & Quantiles | Calculation, Definition & Interpretation
Videos
05:28
Find the Lower Quartile and Upper Quartile - YouTube
06:39
How to Find Quartiles (Even Set of Data) | Math with Mr. J - YouTube
11:46
Quartiles | Lower Quartile, Median, and Upper Quartile | Math with Mr.
05:53
How to Find Quartiles (Odd Set of Data) | Math with Mr. J - YouTube
14:35
Statistics: Quartiles of Grouped Data - YouTube
35:13
Quartiles, Deciles, & Percentiles With Cumulative Relative Frequency ...
BYJUS
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Quartiles Definition
November 27, 2019 - In statistics, Quartiles are the set of values which has three points dividing the data set into four identical parts. We ordinarily deal with a large amount of numerical data, in stats. There are several concepts and formulas, which are extensively applicable in various researches and surveys.
Futrli
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An introductory guide to calculating and using quartiles
November 10, 2021 - If you had 'N' number of data points, the formulas for the quartiles would look as follows: Lower Quartile (Q1) = (N+1) * 1/4. When working with large sets of data, it is generally easier to make use of the QUARTILE function in Microsoft Excel.
Study.com
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Finding the Lower Quartile | Definition, Calculation & Examples - Video | Study.com
June 29, 2019 - This is the same as slicing the cake into two equal parts and then taking one of those parts to cut again to obtain one-quarter of the cake. The other method is to solve using the formula {eq}Q_1 = \frac{1}{4}(n+1) {/eq}, where n is the total ...
Reddit
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r/askmath on Reddit: Calculating quartile
December 6, 2022 -
Hello everyone, I have the calculator TI-30X pro. This calculator allows to calculate quartiles (Q1 and Q3). I face an issue as the machine gives me Q3 as 24 even though the value doesn’t exist in my data set. The answer from our school is Q3 = 23 Here is my data set : 23, 21, 18, 19, 20, 18, 30, 25, 18
Thanks in advance for your help :)
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To find the third quartile, or Q3, we need to first arrange the data set in numerical order. This would give us: 18, 18, 18, 19, 20, 21, 23, 25, 30 To find Q3, we need to first find the median, or middle value, of the data set. We do this by dividing the number of values in the set by 2. In this case, we have 9 values, so the median would be the value at the 9/2 = 4.5th position. Since we can't have a half value, we need to take the average of the two values that surround this position, which are the values at the 4th and 5th positions. In this case, these values are 19 and 20, so the median would be (19 + 20) / 2 = 19.5. Now that we know the median, we can find the third quartile by finding the median of the values that are greater than the overall median. In this case, we have the values 21, 23, 25, and 30. The median of these values is (23 + 25) / 2 = 24, so Q3 is 24. Therefore, the third quartile, or Q3, of the data set is 24.
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Statistics How To
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What are Quartiles? - Statistics How To
September 6, 2024 - Work the formula. There are 11 numbers in the set, so: Q3 = ¾(n + 1)th Term. Q3 = ¾(11 + 1)th Term. Q3 = ¾(12)th Term. Q3 = 9th Term. In this set of numbers (1, 2, 5, 6, 7, 9, 12, 15, 18, 19, 27), the upper quartile (18) is the 9th term, ...
Scribbr
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Quartiles & Quantiles | Calculation, Definition & Interpretation
June 21, 2023 - To find a q-quantile, you can follow a similar method to that used for quartiles, except in steps 3–5, multiply n by multiples of 1/q instead of 1/4. ... Calculate n * (3 / 5). If n * (3 / 5) is an integer, then the third 5-quantile is the ...
Cuemath
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Quartile Formula - What is Quartile Formula?
The quartile formula helps to divide a set of observations into 4 equal parts. The first quartile lies in the middle of the first term and the median. The median is the second quartile.
Wikipedia
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Quartile - Wikipedia
October 30, 2025 - {\displaystyle p=0.75} for the third quartile. The quantile function is the inverse of the cumulative distribution function if the cumulative distribution function is monotonically increasing because the one-to-one correspondence between the input and output of the cumulative distribution function holds. There are methods by which to check for outliers in the discipline of statistics and statistical analysis.
MathsisFun
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Quartiles
Quartiles are the values that divide a list of numbers into quarters.
Data Science Discovery
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Quartiles and Box Plots - Data Science Discovery
Visually, we can see the data split into the four quartiles by the Q1, Q2 and Q3: Frequency histogram of a difficult exam. Calculating Q2: To find Q2, all we have to do is calculate the median of the data · Calculating Q1 and Q3: To find Q1 and Q3, we want to be as exact as possible. We can't just take the midpoint of two data points. Instead we use the following formula first to find the true index location:
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Quartile Calculator | Interquartile Range Calculator
November 4, 2025 - The formula for maximum is: \[ \text{Max} = x_n = \text{max}(x_i)_{i=1}^{n} \] The range of a data set is the difference between the minimum and maximum. To find the range, calculate xn minus x1. \[ R = x_n - x_1 \] ... [1] Wikipedia contributors. "Quartile." Wikipedia, The Free Encyclopedia. Last visited 10 April, 2020. ... This article provides authoritative insights around Statistics topics and calculations, and provides a free Quartile Calculator tool.
Statistics Canada
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4.5.1 Calculating the range and interquartile range
The interquartile range and semi-interquartile range give a better idea of the dispersion of data. To calculate these two measures, you need to know the values of the lower and upper quartiles. The lower quartile, or first quartile (Q1), is the value under which 25% of data points are found when they are arranged in increasing order.
Investopedia
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Understanding Quartiles: Definitions, Calculations, and Examples
August 3, 2025 - Quartiles are values that split lists of datasets into quarters, resulting in lower, middle, and upper segments. Quartiles are statistical measures that divide a data set into four equal parts, each representing 25% of the observations. By arranging data points in increasing order, you can identify three quartile values: the lower quartile, median quartile, and upper quartile.
BBC
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Quartiles and interquartile range - Range and box-and-whisker plots - WJEC - GCSE Maths Numeracy (WJEC) Revision - BBC Bitesize
February 27, 2023 - To find these from the graph we draw two lines across from the vertical axis, one at 10 and one at 30. We read the values for the quartiles from the graph and arrive at 38 and 47. You are allowed to be out by a little but be as accurate as you can. So the interquartile range is the difference between the upper quartile and lower quartile.
W3Schools
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Statistics - Quartiles and Percentiles
For example, The 95th percentile separates the lowest 95% of the values from the top 5% The 25th percentile (P25%) is the same as the first quartile (Q1). The 50th percentile (P50%) is the same as the second quartile (Q2) and the median.
Outlier
articles.outlier.org › what-are-quartiles-in-statistics
What Are Quartiles? Statistics 101 | Outlier
March 26, 2023 - In statistics, quartiles divide your data into four equal groups, each containing 25% (or a quarter) of your data points.
GeeksforGeeks
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Quartile Formula: Calculation, Examples, Quartile vs Percentile - GeeksforGeeks
January 25, 2022 - Quartiles divide a data set into four equal parts, each containing 25% of the data. They help to understand the spread and center of the data. As an important concept in statistics, quartiles are used to analyze large data sets by highlighting ...
Taylor & Francis Online
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Full article: Quartiles in Elementary Statistics
As was noted by CitationFreund ... to the quartiles Qi (i = 1, 2, 3) yield, respectively, , , and , and that these can be viewed as the special cases = 0, 0.5, 1 of the general formula . The generalizations of these to arbitrary quantiles are #((n — 1)p + 1), #(np + 0.5), #((n + 1)p), and . Other values of are used in the literature ...