A Histogram is a pictorial representation of a set of data, and the most commonly used bar graph for showing frequency distributions of data/values.
It is created by grouping the measurements into “cells” or “class ” or “bins”.
It is similar to the bar chart, but it groups data points into classes and plot frequencies.
Histogram graph is considered one of the basic 7 QC Tools or Seven Basic Quality Improvement Tools and is extensively used in SPC, Lean Manufacturing, and problem-solving techniques such as 8D, PDCA, and Six Sigma.
Table of Contents
WHEN TO USE A HISTOGRAM
-To summarize large data sets graphically.
-To compare measurements to specifications.
-Assist in decision making.
PURPOSE OR BENEFITS OF HISTOGRAM
– A bar graph that shows the frequency distribution of values/data.
– To assess process capability & to understand variation.
– Useful to understand the spread or variations, location, and shape of the data.
– To know whether a process is stable and predictable.
– To know whether the process produces within specification.
– Process monitoring and centering.
HISTOGRAM IN EXCEL | HISTOGRAM WITH EXAMPLE
Steps for constructing a Frequency distribution graph or Histogram in excel are as follows:
1-Count the number of data points ‘n’.
2- Compute the range of data. The range ‘R’ is the difference between the largest and the smallest value in the sample.
3- Determine the number of classes or intervals i.e. class size
4- Compute class width.
5- Prepare the Tally sheet or Check sheet by summarizing data on it.
6- Count the number of parts in each interval i.e. Number of frequencies within a particular class.
7- Now plot the graph. Place frequencies on the vertical axis, and class intervals on the horizontal axis.
8- Interpret the histogram by seeing the shape distribution.
INTERPRETATION OF HISTOGRAM
See also:
- Quality Meaning and Definitions by Quality Gurus
- TQM | TOTAL QUALITY MANAGEMENT | TQM Meaning
- Stratification Meaning | Stratification Definitions | Benefits with Examples
- What is Scatter Diagram? Correlation Chart | Scatter Graph
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