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This is the second part of a general introduction to BI using a case study of a mobile phone store.
How Many? – this relates to the quantity of items handled by the enterprise and and measures are done over fixed periods of time (e.g. monthly, yearly or even since the start of the enterprise).
A lot of enterprise report this data as tabular or bar chart forms, but proper analysis can often reveal much more than what the data seems to represent. For example, here is the number of phones sold by a high street shop on a monthly basis:
Figure 1 shows a conventional bar chart plot of table 1. Neither the table nor the bar chart is of much use because none of the representation give us any added visual information. The only information one can clearly extract from figure 1 as opposed to table 1, is that certain phone categories outsell others.
Figure 2 is the same same data as figure 1 but the visual information is much clearer and straight away we see a trend appearing in the data: April and October are high sale months across all phone categories. There also seem to be a decline in some sales, but this is more difficult to spot from this graph. To reveal this trend, we need to apply a differential analysis. This is shown in figure 3 below.
The 2nd trend now appears much more prominently in figure 1.3, while all phones show prominent sales in the months of April and October, only Android phones show an increase in sales, all the other categories are in decline.
This result would be the start of an analysis exercise to answer the questions that naturally arise from this conclusion. Why are phone sales in decline, is it a general market trend or specific to the shop? Why are Android phones sales on the increase? Is it a market trend? Is it at the expense of other types of phones? These are some the questions the executive management would want to find answers to. Market data and past years performance of the shop would be required to fully answer these questions.