SCATTERED DIAGRAM
BASICS
· Scattered diagram was introduced by Francis Galton.
· It is used for to check the relationship between two variables, where one variable is plotted on horizontal x-axis and other is plotted on vertical y-axis.
· The pattern made by intersecting point’s shows relationship between two variables.
· It uses the data collected for the cause and effect diagram and shows our cause and effect diagram is effective or not.
· Scattered diagram shows that the two variables are made from common cause that is unknown.
USE OF THE SCATTERED DIAGRAM
· It is used for the cause and effect diagrams analysis, the results from fishbone diagram is taken and find the root causes of identified problem.
· Scattered diagram is used where two different effects are occurred by same cause.
· It is used when two variables having some interrelations.
STEPS TO MAKE A SCATTERED DIAGRAM
Collection of data
· Collect the 80-100 pairs of sample variables which shows possible relationship between them.
· Data may be from any process interconnected steps or any assembly of two parts etc.
Diagram preparation
· Prepare the rough diagram which include x as a horizontal axis and y as a vertical axis.
· Give the labels to the axes in the multiplication value so that maximum number of variables can include into the diagram.
· You may give the labels in such a way that on vertical axis numbering goes increasing from bottom to top and on horizontal axis numbering goes increasing from left to right.
Plotting on graph/diagram
· Plot all the data in the circular dots formats on the diagram.
CORRELATIONS
· Positive correlation: if on the diagram between x axis and y axis the parameters of both axis is in increasing order then it is called the positive correlation.
· Example: if we taking two variable like age of child and height of child then we get positive correlation.
· Negative correlation: if on the diagram between x axis and y axis the parameters of both axis is in decreasing order then it is called the positive correlation.
· Example: if the temperature of atmosphere or weather gets colder cost of Air conditioner decreases.
· No correlations: when the points on diagram are scattered here and there that means far away from each other then there is no correlation between them those diagrams are under the category of no correlation.
· Example: Pen and handwriting are not said that the good pen makes better handwriting hence both are having no correlation.
STRENGTH OF THE CORRELATION AND LINE OF BEST FIT
· Line of best fit means a line drawn between the correlated points on the diagram in such a way that maximum number of points comes on the line or nearer to the line.
· How many points are nearer to the line or found on the line shows the strength of the correlation. Larger the points on the line or near to the line greater the strength of the correlation and vice versa.
Example
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