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#Minitab boxplot how to#
#Minitab boxplot series#

The purpose and methods of analyzing data using these methods is detailed as follows: What is Histogram?

#Minitab boxplot series#

We analyze one parameters for understanding behaviour of process by using (1) Histograms, (2) Box Plots and (3) Time Series Plots. Understanding relationship between multiple parameters.Analyzing one parameter (performance or control).What are the objectives of Graphical Analysis? It can only give direction for decision making and further analysis. Further details on hypothesis testing will be given in our subsequent articles.Ĭaution: Graphical analysis should never be used for concluding. Graphical analysis clearly indicates which alternate hypothesis is the best option. In this case, the risk of decision doubles compared to when alternate hypothesis is "less than" or "greater than". If graphical analysis is not used, the only option of alternate hypothesis is "not equal to". In the Hypothesis Testing, the alternate hypothesis can be any one of the three options viz.

What is the basis of Alternate Hypothesis? If graphical analysis was not done the data will be collected in irrelevant ranges wasting our resources. For example, if graphical analysis indicates values are increasing, we need to collect data on higher side only for further validation of what is happening in process. We should direct our resources for further analysis based on graphical analysis.

#Minitab boxplot how to#

How to decide direction of data collection? It allows all types of graphical presentation required for quick decisions. Minitab makes graphical analysis very simple. The purpose of graphical analysis is to have fair estimation of what is happening in the process apart from rationalizing resources and setting direction of decision making. Notice the interquartile range between the 25 th and 75 th quartiles, the median line, the mean, and the whiskers.What is the Purpose of Graphical Analysis? Model summary: The above figure demonstrates the result of the boxplot after navigating through the Minitab menus to yield this output.

The box plot appears automatically in the new window.

Click “OK” in the window “Boxplot– One Y, Simple.”.

Click “OK” in the window “Boxplot– Data View.”.

Check the boxes “Mediansymbol” and “Mean ”.

Click the “Data View” button and a new window named “Boxplot– Data View” pops up.

Select “HtBk” as the “Graph Variables.”.

Another new window named “Boxplot– One Y, Simple” pops up.

How to Use Minitab to Generate a Box Plotĭata File: “Box Plot” tab in “Sample Data.xlsx”

The ends of the whiskers represent the maximum and minimum of the data, and the individual dots beyond the whiskers represent outliers in the data set. The whiskers on either side of the IQR represent the lowest and highest quartiles of the data. The line near the middle of the box represents the median (or middle value of the data set). The middle part of the plot, or the “interquartile range,” represents the middle quartiles (or the 75th minus the 25th percentile). Here are a few explanations that may help. The figure above describes how to read a box plot. At the 50th percentile, or median, 50% of the values are lower and 50% are higher than that value. For example, if 75% of the observations have values lower than 685 in a data set, then 685 is the 75th percentile of the data. A percentile is the value below which a certain percentage of data fall. A box plot is a graphical method to summarize a data set by visualizing the minimum value, 25th percentile, median, 75th percentile, the maximum value, and potential outliers.