An

**outlier**is an observation that is numerically distant from the rest of the data. When reviewing a**boxplot**, an**outlier**is defined as a data point that is located outside the fences (“whiskers”) of the**boxplot**(e.g: outside 1.5 times the interquartile range above the upper quartile and bellow the lower quartile).People also ask, how do you find the upper and lower fences?

**Step 2: Insert the values from Step 1 into the formulas and solve:**

- Lower inner fence: Q1 – (1.5 * IQR) = 540 – (1.5 * 463) = -154.5.
- Upper inner fence: Q3 + (1.5 * IQR) = 1003 + (1.5 * 463) = 1697.5.
- Lower outer fence: Q1 – (3 * IQR) = 540 – (3 * 463) = -849.
- upper outer fence: Q3 + (3 * IQR) = 1003 + (3 * 463) = 2392.

What is an upper and lower fence?

The

**Lower fence**is the "**lower**limit" and the**Upper fence**is the "**upper**limit" of data, and any data lying outside this defined bounds can be considered an outlier. LF = Q1 - 1.5 * IQR.1

## What defines an outlier?

**Outlier**. For example, the point on the far left in the above figure is an

**outlier**. A convenient definition of a

**outlier**is a point which falls more than 1.5 times the interquartile range above the third quartile or below the first quartile.

**Outliers**can also occur when comparing relationships between two sets of data.

2

## Is the mean or median more affected by outliers?

In a distribution with an odd number of observations, the

**median**value is the middle value. The**median**is less**affected by outliers**and skewed data than the**mean**, and is usually the preferred measure of central tendency when the distribution is not symmetrical.3

## What does the range of data tell you?

The

**range**can only**tell you**basic details about the spread of a set of data. By giving the difference between the lowest and highest scores of a set of data it gives a rough idea of how widely spread out the most extreme observations are, but gives no information as to where any of the other data points lie.4

## What are outliers in a data set?

In statistics, an

**outlier**is an observation point that is distant from other observations. An**outlier**may be due to variability in the measurement or it may indicate experimental error; the latter are sometimes excluded from the**data**set.5

## How do you find an outlier?

A point that falls outside the

**data set's**inner fences is classified as a minor**outlier**, while one that falls outside the outer fences is classified as a major**outlier**. To**find**the inner fences for your**data set**, first, multiply the interquartile range by 1.5. Then, add the result to Q3 and subtract it from Q1.6

## How do you find the range in a box plot?

**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). In the above graph, Q1 is approximately at 2.6.
- Step 2: Find Q3.
- Step 3: Subtract the number you found in step 1 from the number you found in step 3.

7

## What is an outlier in a box plot?

These "too far away" points are called "

**outliers**", because they "lie outside" the range in which we expect them. The IQR is the length of the**box**in your**box**-and-whisker**plot**. An**outlier**is any value that lies more than one and a half times the length of the**box**from either end of the**box**.8

## What does it mean if a person is an outlier?

An “

**outlier**” is anyone or anything that lies far outside the normal range. In business, an**outlier**is a**person**dramatically more or less successful than the majority. Do you want to be an**outlier**on the upper end of financial success? Certainly.**Outliers**is also a very popular book by Malcolm Gladwell.9

## What is a interquartile range?

In descriptive statistics, the interquartile range (

**IQR**), also called the midspread or middle 50%, or technically H-spread, is a measure of statistical dispersion, being equal to the difference between 75th and 25th percentiles, or between upper and lower quartiles,**IQR**= Q_{3}− Q_{1}. In other words, the**IQR**is the first10

## What is an outlier in a dot plot?

An

**outlier**is a value in a data set that is very different from the other values. That is,**outliers**are values unusually far from the middle. In most cases,**outliers**have influence on mean , but not on the median , or mode .11

## What is the formula for outliers?

2. Calculate first quartile (Q1), third quartile (Q3) and the in- terquartile range (IQR=Q3-Q1). CO2 emissions example: Q1=0.9, Q3=6.05, IQR=5.15. 3. Compute Q1–1.5 × IQR (=–6.825) Compute Q3+1.5 × IQR (=13.775) Anything outside this range is an

**outlier**.12

## What is an outlier in data?

What are

**outliers**in the**data**? Definition of**outliers**. An**outlier**is an observation that lies an abnormal distance from other values in a random sample from a population. In a sense, this definition leaves it up to the analyst (or a consensus process) to decide what will be considered abnormal.13

## How does an outlier affect the mean and standard deviation?

Thus, it measures spread around the

**mean**. Because of its close links with the**mean**,**standard deviation**can be greatly**affected**if the**mean**gives a poor measure of central tendency.**Standard deviation**is also influenced by**outliers**one value could contribute largely to the results of the**standard deviation**.14

## How does the removal of the outliers affect the box and whisker plot?

**Outliers**are important because they are numbers that are "outside" of the

**Box Plot's**upper and lower fence, though they don't

**affect**or change any other numbers in the

**Box Plot**your instructor will still want you to find them. If you want to find your fences you will first take your IQR and multiply it by 1.5.

15

## What is a box and whisker plot?

A

**box and whisker plot**(sometimes called a**boxplot**) is a graph that presents information from a five-number summary. In a**box and whisker plot**: the ends of the**box**are the upper and lower quartiles, so the**box**spans the interquartile range. the median is marked by a vertical line inside the**box**.16

## What is an outlier on a box and whisker plot?

In order to be an

**outlier**, the data value must be: larger than Q3 by at least 1.5 times the interquartile range (IQR), or. smaller than Q1 by at least 1.5 times the IQR.17

## How do you calculate the interquartile range?

Consider the set: 1, 2, 3, 4, 5, 6, 7, 8. Learn the

**formula**. In order to find the difference between the upper and lower quartile, you'll need to subtract the 25th percentile from the 75th percentile. The**formula**is written as: Q3 – Q1 =**IQR**.