So after looking at the Check Sheet as a tool number one, Cause and Effect Diagram as tool number two. 2
Now here we are tool number three which is Histogram and what is a histogram, histogram is a bar chart 3
that displays the frequency of individual measurements in case of a water bottle example which we took 4
earlier. 5
Let's say if I'm looking at 1000 ml. bottles and I take number of samples and start measuring 6
those. 7
So the first I pick 8
that shows that this has 1000 ml, second bottle I pick 9
that shows that this has nine hundred and ninety five ml. 10
I know that five ml in the water bottles might not be a big deal. 11
Let's hypothetically take this, let's think that water is a very valuable water like each cc matters a 12
lot. 13
So once you have collected thousands of these readings related to that water volume in each of these 14
bottles you can make a histogram. Histogram will tell you that what's the trend in the bottles which you're 15
feeling. 16
You might see that most of the bottles which you are feeling as a 1000 ml might have a volume 17
over 956cc only but all those links you can see once you draw a histogram of that. I am not going to that complex 18
example I keep it very simple. 19
My simple example here is that I need to reach my office exactly at 6:30 a.m. Now do I reach there at 20
21 6:30 a.m. every day no sometimes I reach 10 minutes early, Sometimes I reach five minutes early. 22
Sometimes I reach 15 minutes late. 23
So what they do is over a period of time I keep collecting that information that every day I go and 24
make a record of that. 25
So I went to office and instead of 6:30 a.m. I reached there at 6:25. 26
So I keep a note of that next day I reach there at 6:30 27
I keep a note of that. 28
And based on that I will draw a histogram which will tell that what my trend reaching office, what 29
time do I really reach. 30
Do I have too much of variation in my reaching time. 31
Do I just reach within plus minus five minutes. 32
I can see that once I draw the histogram and that I'll be doing on the next slide. 33
But let's quickly look at here on this slide that why do we need a histogram. 34
We need histogram to visualize the spread and to visualize the center point. 35
What's the average time I reach and what's my spread that we will see once I look at the histogram and this 36
provides the clue to reduce variation and this can help us in thinking about the cause of the problem. 37
If we are off center like instead of 6:30 most of the times if I reach 7:00 then there's a problem 38
somewhere there's a problem I need to correct. 39
What other reason could be the spread is too high. 40
Sometimes I reach let's say 5:30, sometimes I reach 7:30 instead of 6:30 then I need to control the spread 41
of my arrival time in the office. 42
All these things I can do once I draw the histogram once I look at the shape of that. Let's move on to 43
the next slide and look at that example of my office reaching time.