How do box plots work?
Box plots make it easy to visualize the differences among data sets. This makes it quick and easy to compare data sets, and even more so if you learn how to make box plots on excel or google sheets. Statistics can also use box plots with labels to visually display multiple parameters simultaneously.
Graphical Analysis is an effective way to analyze Six Sigma projects. It gives insight into data and can be used to visualize data patterns. There are many graphic tools available, including Chart. Scatter Diagrams Histograms, Pareto chart display different characteristics of data such as the frequency, dispersion and shape of distribution. A box plot (also known as Whisker plot) is a visual representation of continuous data. The box plot shows the Max, Min and median values as well as interquartile range Q1,Q3, and outlier.
To show the second and three quartiles, rectangles can be used. The Median value is indicated by a vertical line. Horizontal lines are drawn on both sides of the rectangle to indicate the lower or upper quartiles. The lines that run vertically from the boxes are what give the box its name, whisker. These lines show the variation between the lower and higher quartiles.
- The first quartile (0-25%)
- Troisième quartile (75%)
Why use box plots?
Labeled box plots can be very helpful and easy to understand. This graphically displays the variation between multiple variables and the variations within each range.
This is also called a box-and-whisker plot or “five number summary”. It also includes medians and quartiles as well as the highest or most important values. This chart illustrates how data within these ranges can help in decision-making.
They are easy to make when you learn how to make a box plot on excel or google sheets.
When is it appropriate to use box plots
- These tools will allow you to compare data sets and determine if there is any relationship.
- It is possible to compare the results of the improvement process before and after.
- These allow you to quickly display various parameters
- You can view the median, interquartile range and outliers in the data set.
- If the data is in metric scale levels like temperature, age, and so forth.
What can we learn from box plots?
- Middle values The box indicates where the middle half of all data is located
- Median The blue horizontal line shows the median value for the group.
- 1st Quartile and 3rd Quarterile: The lower half of the box corresponds with the 1st quarterile. The upper half corresponds with the 3rd quarterile.
- It’s useful for visualizing the spreads
- Ex. Ex.
- Skewness: You can check if the box line is not center if you have an off-center distribution of data
- Ex. Ex.
- Extreme values The maximum and minimum values are shown by the vertical lines (whiskers).
- Ex. Stock 5 tends have higher values
- Data that is not between whiskers should always be plotted using outliers, dots, small circles, and stars
- Box plots can also include an extra character to represent the average of the sample data
- Some whisker plots use cross-hatch. All box plots will include whiskers
How to create a box and whisker plot?
These are the steps to follow:
- Collect data: Gather the data needed to create plots
- This will allow you to organize your data. You can sort them numerically by ascending or decreasing.
- Calculate Medians: Find the Median for your data range. This Median divides data into two halves. Calculate the Medians to find the Medians of the two halves. If the data set has an odd number, the Median will have equal numbers for each side. If the data set has even numbers, the Median will have the same number on each side
- Calculate the 1st and 3rd Quartiles. You can calculate the Median for each Half by using this formula
- Next, draw plotlines: Next, draw plotlines and mark Medians and Quartiles