What Quartiles is
Quartiles are used to divide a dataset into four equal parts. Quartiles are used to measure the spread of a dataset and provide a better understanding of the data. The quartiles are used to organize the data into four equal parts and to find the median of the data.
Steps for Quartiles:
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Arrange the data in numerical order from smallest to largest.
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Calculate the median (middle number) of the data set.
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Split the data set into two halves, one above the median and one below the median.
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Calculate the median of each half to get the first and third quartiles.
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The quartiles divide the data set into four equal parts. The first quartile (Q1) is the median of the lower half of the data; the second quartile (Q2) is the median of the whole data set; the third quartile (Q3) is the median of the upper half of the data.
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The interquartile range (IQR) is the difference between the third and first quartiles (Q3 - Q1). This is another measure of spread.
Examples
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Quartiles can be used to identify the spread of data in a dataset. For example, a quartile analysis of a dataset of exam scores can identify the distribution of scores and which scores are in the upper and lower quartiles.
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Quartiles can also be used to compare the performance of two groups. For example, a quartile analysis of the performance of two classes on a test can determine which class has higher scores in the upper and lower quartiles.
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Quartiles can also be used to identify outliers in a dataset. For example, a quartile analysis of a dataset of employee salaries can identify which salaries are in the upper and lower quartiles, as well as any outliers.