Histogram is an important tool out of seven quality tools to present the data in graphical form and describes the properties of the data. Histogram showcases the spread of the data. Histogram describes the Skewness in the data. Histogram presents the frequency distribution of the data by vertical rectangular bars. The categories of the data are taken on X-Axis and frequencies of different categories are taken on Y-Axis. Histogram is a statistical process control technique. Histogram shows the symmetric distribution of the data and check if the data is normally distributed. Histogram can be constructed for grouped distribution and ungrouped distribution. For ungrouped data the frequencies are calculated by means of tally marks and then the frequencies of different data categories are shown on the graph by rectangular vertical bars. For grouped data i.e. when data is given in groups or in class intervals. Find the frequencies of the different class intervals. Class intervals are taken on X-Axis and frequencies of different class intervals are taken on Y-Axis. Vertical rectangular bar chart is so prepared and then analyze.

1. SEVEN QC TOOLS TRAINING
Histogram

2. SEVEN QC TOOLS TRAINING: HISTOGRAM
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Introduction Histogram is an important tool which presents a large amount of data graphically and describes the properties of data. Histogram is the graphical presentation of the data by rectangular adjacent bars. Class of data is taken on X-Axis, while the height of the bars shows the frequency of the class. Histogram showcases the spread of data.

3. SEVEN QC TOOLS TRAINING: HISTOGRAM
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Histogram showcases the Skewness in the data. Skewness in the data is the result of absence of symmetry in the data. Histogram pictured this symmetric absence in the data by means of a line curve drawn by meeting the mid-points of heads of rectangular bars. If there is no Skewness in the data the curve will be a normal curve and this confirms symmetric distribution of data.

4. SEVEN QC TOOLS TRAINING: HISTOGRAM
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Histogram for Ungrouped data Arrange the raw data into ascending or descending order. Calculate the frequency of data using tally marks. We can use check sheet for the data collection purpose. Take data headings on X-Axis and their respective frequencies on Y-Axis and construct a Histogram.

5. SEVEN QC TOOLS TRAINING: HISTOGRAM
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Histogram for Grouped data To make a histogram for grouped data we need to arrange the data into equal class intervals in ascending or descending order. To arrange data into class intervals, first we calculate No. of Class intervals and then the width of Class Interval.

6. SEVEN QC TOOLS TRAINING: HISTOGRAM
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General Formulae for calculating No. of Class interval and width of class interval is given as
( ) ( )
Where ‘n’ is the total no. of observations. Width and No. of Class interval can be set according to suitability and volume of the data.

7. SEVEN QC TOOLS TRAINING: HISTOGRAM
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Calculate the frequency of data for different class intervals and draw the Histogram taking class interval on X-Axis and frequencies on Y-Axis.

8. SEVEN QC TOOLS TRAINING: HISTOGRAM
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Shapes of Histogram

9. SEVEN QC TOOLS TRAINING: HISTOGRAM
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Histogram; an SPC Techniques

10. SEVEN QC TOOLS TRAINING: HISTOGRAM
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Construction of Histogram
One hundred components were inspected for their hardness. Observations were recorded as given. Draw a histogram showing variations in hardness
211, 212, 209, 210, 212, 211, 209, 211, 210, 212, 212, 207, 211, 212, 210, 209, 211, 214, 209, 211, 213, 210, 208, 217, 214, 213, 207, 216, 213, 210, 212, 208, 212, 208, 211, 214, 212, 210, 212, 213, 208, 211, 213, 211, 213, 212, 216, 212, 211, 214, 213, 210, 211, 213, 212, 211, 210, 213, 209, 212, 214, 213, 214, 216, 215, 215, 213, 215, 215, 210, 209, 212, 215, 212, 210, 209, 215, 211, 213, 215, 212, 214, 213, 214, 214, 213, 209, 215, 212, 214, 210, 215, 216, 213, 211, 214, 211, 212, 214, 213

11. SEVEN QC TOOLS TRAINING: HISTOGRAM
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Collect the data as given below
Hardness
Tally Marks
Frequency
207
//
2
208
////
4
209
//// ///
8
210
//// //// /
11
211
//// //// ////
15
212
//// //// //// ///
18
213
//// //// //// /
16
214
//// //// //
12
215
//// ////
9
216
////
4
217
/
1
Total
100

12. SEVEN QC TOOLS TRAINING: HISTOGRAM
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Construct the Histogram as given taking Hardness on X- Axis and Frequency on Y-Axis

13. SEVEN QC TOOLS TRAINING: HISTOGRAM
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Contact
Narender Sharma
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Email: shakehandwithlife@gmail.com | narender@shakehandwithlife.in