What does the upper quartile tell us?
The upper quartile is the median of the upper half of a data set. This is located by dividing the data set with the median and then dividing the upper half that remains with the median again, this median of the upper half being the upper quartile. N represents the number of elements in the data set.
How do you divide data into quartiles?
The four quarters that divide a data set into quartiles are:
- The lowest 25% of numbers.
- The next lowest 25% of numbers (up to the median).
- The second highest 25% of numbers (above the median).
- The highest 25% of numbers.
How do you read and interpret quartiles?
How to Calculate Quartiles
- Order your data set from lowest to highest values.
- Find the median. This is the second quartile Q2.
- At Q2 split the ordered data set into two halves.
- The lower quartile Q1 is the median of the lower half of the data.
- The upper quartile Q3 is the median of the upper half of the data.
How do you interpret quartiles and percentiles?
Quartiles are special percentiles.
- The first quartile, Q1, is the same as the 25th percentile. 25% of data will be less than 25th percentile; 75% of data will be more than 25th percentile.
- The second quartile, Q2, is the same as the 50th percentile / median.
- The third quartile, Q3, is the same as the 75th percentile.
What are the uses of quartiles?
Returns the quartile of a data set. Quartiles often are used in sales and survey data to divide populations into groups. For example, you can use QUARTILE to find the top 25 percent of incomes in a population.
Why is it important to study quartiles?
Quartiles let us quickly divide a set of data into four groups, making it easy to see which of the four groups a particular data point is in. For example, a professor has graded an exam from 0-100 points. The middle 50% of the data can useful to know about, especially if the data set has outliers.
How do quartiles apply to real life?
Some companies use the quartiles to benchmark other companies. For example, the median company pay for a given position is set at the first quartile of the top 20 companies in that region. The quartiles and IQR information is typically used when you create a box-plot of your data set.
How do you interpret the first quartile?
To find the smaller quartile, known as Q1, take the median from the smallest number to the median of the whole set. Finally, to find the largest quartile, known as Q3, take the median from the median of the whole set to the largest number.