# What are quartiles in statistics?

## What are quartiles in statistics?

A quartile is a statistical term that describes a division of observations into four defined intervals based on the values of the data and how they compare to the entire set of observations.

## What are quartiles examples?

Example: 5, 7, 4, 4, 6, 2, 8 Quartile 1 (Q1) = 4. Quartile 2 (Q2), which is also the Median, = 5. Quartile 3 (Q3) = 7.

How do you find Q1 and Q3?

Q1 is the median (the middle) of the lower half of the data, and Q3 is the median (the middle) of the upper half of the data. (3, 5, 7, 8, 9), | (11, 15, 16, 20, 21). Q1 = 7 and Q3 = 16.

### What do the quartiles tell you?

Quartiles tell us about the spread of a data set by breaking the data set into quarters, just like the median breaks it in half. This means that when we calculate the quartiles, we take the sum of the two scores around each quartile and then half them (hence Q1= (45 + 45) ÷ 2 = 45) .

### How do you find quartiles examples?

When the set of observations are arranged in ascending order the quartiles are represented as,

1. First Quartile(Q1) = ((n + 1)/4)th Term.
2. Second Quartile(Q2) = ((n + 1)/2)th Term.
3. Third Quartile(Q3) = (3(n + 1)/4)th Term.

How do you find quartiles?

How to Calculate Quartiles

1. Order your data set from lowest to highest values.
2. Find the median. This is the second quartile Q2.
3. At Q2 split the ordered data set into two halves.
4. The lower quartile Q1 is the median of the lower half of the data.
5. The upper quartile Q3 is the median of the upper half of the data.

## How do you find the quartiles Q1 Q2 Q3?

Quartile Formula:

1. Formula for Lower quartile (Q1) = N + 1 multiplied by (1) divided by (4)
2. Formula for Middle quartile (Q2) = N + 1 multiplied by (2) divided by (4)
3. Formula for Upper quartile (Q3) = N + 1 multiplied by (3) divided by (4)
4. Formula for Interquartile range = Q3 (upper quartile) – Q1 (lower quartile)

## Why do we need quartiles?

Why do quartiles matter? 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.

How is quartile calculated?

When the set of observations are arranged in ascending order the quartiles are represented as, First Quartile(Q1) = ((n + 1)/4)th Term. Second Quartile(Q2) = ((n + 1)/2)th Term. Third Quartile(Q3) = (3(n + 1)/4)th Term.

### How do you find quartiles and interquartile ranges?

To find the interquartile range (IQR), ​first find the median (middle value) of the lower and upper half of the data. These values are quartile 1 (Q1) and quartile 3 (Q3). The IQR is the difference between Q3 and Q1.

### How are quartiles calculated?

The formula for quartiles is given by:

1. Lower Quartile (Q1) = (N+1) * 1 / 4.
2. Middle Quartile (Q2) = (N+1) * 2 / 4.
3. Upper Quartile (Q3 )= (N+1) * 3 / 4.
4. Interquartile Range = Q3 – Q1.

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.

## What do the quartiles in math represent?

The quartile measures the spread of values above and below the mean by dividing the distribution into four groups.

• and upper quartile-to form four groups of the dataset.
• which is a measure of variability around the median.
• ## How do you calculate quartile in statistics?

The first method for computing quartiles is to divide your newly ordered dataset into two halves at the median. Find the median, or middle value, of your dataset. For example, if your dataset is (1, 2, 5, 5, 6, 8, 9), the median is 5 because that is the middle value.

What is an example of a quartile?

Financial Definition of quartile. A quartile is one of four equal parts. For example, if we were to look at all of the closing prices for Company XYZ stock for every day in the last year, the top 25% of those prices would represent the upper quartile of the data. The bottom 25% of those prices would represent the lower quartile of the data.

### How do I find the first quartile?

First Quartile. The first quartile can be calculated by first arranging the data in an ordered list, then finding then dividing the data into two groups. If the total number of elements in the data set is odd, you exclude the median (the element in the middle).