Coming to this seventh and the last tool in this series of Seven Basic Quality Tools which is Stratification, 2
stratification means breaking down the data in book categories so that you can make sense out of that. 3
Number of times you have data which is a mixture of many things. 4
And if you look at that you really don't make a good sense of that unless you break that into small 5
pieces. 6
If you remember earlier when we talked of water bottle problems, we talk both loose cap, we talked about 7
wrong labels. 8
We thought that these are two big issues because in that case the first thing which we did was we made 9
a check sheet where we recorded what sort of problem we have with each of these bottles. 10
And then we plotted a pareto chart, based on that pareto chart 11
we concluded that there are two main problems if we solve the problem of loose cap and wrong labels 12
that will eliminate 72 percent of the problems that's what we thought by looking at the pareto chart. 13
But what we missed there was that we were looking at a joint number of three different types of bottles. 14
We had a bottle of 300ml, we had a bottle of 500 ml, we had a bottle of 1000 15
milliliters and we looked at the combined data based on that only we plotted this pareto 16
chart. 17
If you don't remember that go and look at that pareto chart example and then come back here. 18
So the point here is that stratification helps us in breaking down that rather than looking at the big 19
picture. 20
Now you need to break that into a number of pieces. 21
You look at the pareto chart individually for each of these different types of bottles because each 22
type of bottle might have a different set of problems so that what we do in Startification that when 23
data is coming from multiple sources, multiple categories, multiple suppliers, multiple machines you 24
dont look at that as a joint data. 25
You might have to break that separately so that you can look at each suppliers separately. 26
You can look at each machine separately rather than looking at the combined data. 27
Let's get to the next slide and look at that example of water bottle where we segregated the pareto chart 28
which we made for that 29
water bottles problems into three separate pareto chart. 30
So there we will have a better picture of what sort of a problem we have with different types of bottles. 31
Let's move on to the next slide and look at that pareto chart.