4. Scatter plot
a graph in which the values of two variables are plotted along two axes, the
pattern of the resulting points revealing any correlation present.
It contain Series of dots.
6. When to use Scatter plot
This is used to find the correlation.
We have positive correlation, negative correlation and no correlation.
When we have pair numeric data.
Identity the type of relationship between two quantities.
8. Stem and leaf plot
A Stem and Leaf Plot is a special table where each data value is split into a
"stem" (the first digit or digits) and a "leaf" (usually the last digit). Like in this
example:
Stem "1" Leaf "5" means 15
Stem "1" Leaf "6" means 16
Stem "2" Leaf "1" means 21
9. When To use Stem and leaf plot
The "stem" is used to group the scores and each "leaf" shows the individual scores within each
group.
Long Jump Example
Sam got his friends to do a long jump and got these results:
2.3, 2.5, 2.5, 2.7, 2.8 3.2, 3.6, 3.6, 4.5, 5.0
Stem Leaf
2 3 5 5 7 8
3 2 6 6
4 5
5 0
10. Tools to find the stem and leaf plot
Stem and leaf plot in excel
Minitab
Matlab
11. Box and Wisker plot or Box plot
The box plot ( box and whisker diagram) is a standardized way of displaying
the distribution of data based on the five number summary: minimum, first
quartile, median, third quartile, and maximum.
12. For Example
Find Q1, Q2, Q3 from given below set and identify outlier and draw box-plot
Data Set: 5,40,42,46,48,49,50,50,52,53,55,56,58,75,102
Q2=50
Q1=46
Q3=56
IQR=Q3-Q1 that is 10
No we need to find the values less than Q1-(1.5*IQR)or greater than
Q3+(1.5*IQR)
13. Example Continue…
Q1-(1.5*IQR), 46-15=31
Q1-(1.5*IQR), 56-15=71
Now 5 is less than 31 and 75 and 102 are greater than 71 so we have 3 outlier
in this case.
Diagram of Box-Plot
14. When to use Box Plot
This helps to find the outlier in our data sets.
Outlier
If the data value is very far away form the quartiles ( Either much less than Q1
and much greater than Q3 ) is referred to outlier.
16. Histogram
A graphically display of data using bars of different heights.
It consist of title, Horizontal or X axis, bars, Vertical or Y axis.
17. When to use Histogram
Summarize large data sets graphically
Compare measurements to specifications
Communicate information to the team
Assist in decision making