BOX PLOT STAT.pptx

It describes box plots in statistics.

1. Topic: BOX PLOTs Presented By: ALI HAIDER ROLL number : 0003.BS.ZOO.2019 semester: 4th Group No. 4 department : Zoology

2. Table of content: Introduction of Box Plot Parts of Box Plot Box Plot Anatomy Other terms used in Box Plot Applications Box plot distribution Steps in making Box Plot Example

3. Introduction Box plots is defined as: “ A Box Plot shows the distribution of a set of data along a number line, dividing the data into four parts using the median and quartiles.” The term “box plot” refers to an outlier box plot; this plot is also called a box-and-whisker plot or a Tukey box plot. Mathematician John Tukey first introduced the “Box and Whisker Plot” in 1969 as a visual diagram of the “Five Number Summary” of any given data set. Box plots can be drawn either vertically or horizontally.

4. Parts of Box Plots A box plot is made up of a box and two ‘whiskers’ Box: The ends of the box are the upper and lower quartiles so that the box crosses the interquartile range A vertical line inside the box marks the median Whiskers: The two lines outside the box are the whiskers extending to the highest and lowest observations.

5. Box Plot Anatomy A box and whisker plot displays the visual representation of five-number summary of a data set. A Five Number Summary includes: Minimum Value First Quartile Median (Second Quartile) Third Quartile Maximum Value

6. Minimum: The minimum value in the given dataset First Quartile (Q1): The first quartile is the median of the lower half of the data set. Median: The median is the middle value of the dataset, which divides the given dataset into two equal parts. The median is considered as the second quartile. Third Quartile (Q3): The third quartile is the median of the upper half of the data. Maximum: The maximum value in the given dataset.

7. OTHER TERMS IN BOX PLOT Apart from these five terms, the other terms used in the box plot are: Interquartile Range (IQR): The difference between the third quartile and first quartile is known as the interquartile range. IQR = Q3-Q1 Outlier: The data that falls on the far left or right side of the ordered data is tested to be the outliers. Generally, the outliers fall more than the specified distance from the first and third quartile. Outliers are greater than Q3+(1.5 . IQR) or less than Q1-(1.5 . IQR).

8. APPLICATIONS: A boxplot is a graph that gives you a good indication of how the values in the data are spread out. Box plots are useful as they show the skewness of a data set . Box plots are useful as they show the dispersion of a data set. Box plots are useful as they show outliers within a data set.

9. Box plot distribution Positively Skewed: If the distance from the median to the maximum is greater than the distance from the median to the minimum, then the box plot is positively skewed. Negatively Skewed: If the distance from the median to minimum is greater than the distance from the median to the maximum, then the box plot is negatively skewed. Symmetric: The box plot is said to be symmetric if the median is equidistant from the maximum and minimum values.

10. steps in Making a Box-and-Whisker Plot  Use the given data to make a box-and-whisker plot. 21, 25, 15, 13, 17, 19, 19, 21 Step 1. Order the data from least to greatest. Then find the minimum, lower quartile, median, upper quartile, and maximum. minimum: 13 maximum: 25 lower quartile = = 16 Upper quartile = 21 Median: = 19

11. Step 2. Draw a number line and plot a point above each value from Step 1.

12. Step 3. Draw the box and whiskers.

13. EXAMPLE 02 Use the given data to make a box-and-whisker plot. 31, 23, 33, 35, 26, 24, 31, 29 Step 1. Order the data from least to greatest. Then find the minimum, lower quartile, median, upper quartile, and maximum. minimum: 23 maximum: 35 lower quartile: = 25 upper quartile: = 32 median: = 30

14. Step 2. Draw a number line and plot a point above each value.

15. Step 3. Draw the box and whiskers.

16. THANK YOU