# Example Library

Box plots are most useful when comparing between several data sets. They are less detailed than histograms, and take up less space which make them easier to compare.

Box plots can tell if the distribution is symmetrical or skewed. In a symmetric distribution, the mean and median are nearly the same, and the two whiskers has almost the same length.

Box plots are ideal to represent moderate to large amount of data. The size of the box plot can vary significantly if the data size is small.

The following are boxplots that display the yield of a crop after applying two different fertilizers. Fertilizer 2 appears to have a higher yield than Fertilizer 1.

This example shows that females have higher glucose levels than males in a workplace. ANOVA can be used here to test the significance of the difference between the two means.

Both histograms and boxplots allow to visually assess the central tendency, the amount of variation in the data as well as the presence of gaps, outliers or unusual data points.

Many statistical applications allow the option of summarizing your data graphically. This can reveal unusual observations before performing detailed statistical analysis.

Scatter diagrams can indicate several types of correlation.

You can indicate a stratification factor in the scatter diagram.

No correlation does not mean there is no cause-and-effect relationship. There might be a relationship over a wider range of data.

This is an analysis that shows the relationship between two variables. The scatter diagram suggests that the two variables are correlated.
(Data source: Minitab Inc)

This analysis was conducted for diagnosing the presence of diabetes at a workplace. It suggests that there is no obvious relationship between age and glucose levels.

In this matrix plot, it appears that there is a positive relationship between the years of experience and salaries.
(Data source: Minitab Inc)

This is an example of a product family matrix which can help choosing the product or family of products that will be of most value.

Value stream mapping uses a set of symbols to denote the various details. These are the basic symbols that are applicable in most situations.

In a value stream map, the information flow is commonly placed at the top, material flow at the middle, and the VSM timeline are placed at the bottom of the map.

This is an example of a current state value stream map for a typical manufacturing process.

Value stream mapping can also be applied in service-related industries such as healthcare, hospitality and logistics. This example illustrates a value stream map for an equipment installation process.

This is an example of a current state value stream map that was created for a specific product family in a manufacturing facility.

Final yield (FY) is widely used yield metric that is easy to calculate. This is an example of a 3-step process map which has a final yield equals that is equal to 90%.