## How do you find the quartiles in a box-and-whisker plot?

## How do you find the quartiles in a box-and-whisker plot?

The first step in constructing a box-and-whisker plot is to first find the median (Q2), the lower quartile (Q1) and the upper quartile (Q3) of a given set of data. You are now ready to find the interquartile range (IQR). The interquartile range is the difference between the upper quartile and the lower quartile.

**What are quartiles box and whisker?**

The whiskers are the two lines outside the box, that go from the minimum to the lower quartile (the start of the box) and then from the upper quartile (the end of the box) to the maximum.

### How do you find the Q1 box and whisker?

Box Plot interquartile range: How to find it

- Step 1: Find Q1. Q1 is represented by the left hand edge of the “box” (at the point where the whisker stops).
- Step 2: Find Q3.
- Step 3: Subtract the number you found in step 1 from the number you found in step 3.

**How do you find the 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 find quartiles examples?

Quartiles are the values that divide a list of numbers into quarters: Put the list of numbers in order. Then cut the list into four equal parts….In this case all the quartiles are between numbers:

- Quartile 1 (Q1) = (4+4)/2 = 4.
- Quartile 2 (Q2) = (10+11)/2 = 10.5.
- Quartile 3 (Q3) = (14+16)/2 = 15.

**How do you calculate quartiles?**

The formula for quartiles is given by:

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

## How do you find Q1 Q2 and Q3?

There are four different formulas to find quartiles:

- Formula for Lower quartile (Q1) = N + 1 multiplied by (1) divided by (4)
- Formula for Middle quartile (Q2) = N + 1 multiplied by (2) divided by (4)
- Formula for Upper quartile (Q3) = N + 1 multiplied by (3) divided by (4)

**How do you calculate Q1?**

### How do you find Q1 Q2 Q3 and Q4?

Quartile Formula:

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

**How do you find the 1st and 3rd quartile?**

#### How to create a box and whisker plot?

– n -the number of observation the boxplot is drawn with (notice that NA ‘s are not taken into account) – conf -upper/lower extremes of the notch, out -value of the outliers – group -a vector of the same length as out whose elements indicate to which group the outlier belongs and – names -a vector of names for the groups.

**How to evaluate a box and whisker plot?**

– Range – 75 – Lowest value – 15 – Interquartile range – 43 – Upper quartile – 68 – Median – 44

## What is the scale on a box and whisker plot?

Median (Q2/50th percentile): The middle value of the dataset

**What is the 5 number summary for a box and whisker plot?**

The five-number summary consists of the numbers I need for the box-and-whisker plot: the minimum value, Q1 (being the bottom of the box), Q2 (being the median of the entire set), Q3 (being the top of the box), and the maximum value (which is also Q4 ).