SarnesCo is a manufacturer of machinery for the textile industry. Company's management has taken up the task of improving the productivity on the assembly line. Accordingly the company appointed consultants presented their report, which when implemented also resulted in some improvement for the company.
The range between the first and third quartiles includes half of the data. The size of the range (i.e., the difference between the third quartile and the first quartile) is another measurement of variability called the inter-quartile range or IQR. For normally distributed data:
Taking a look at the mean, median figures of the production efficiency 'before' and 'after' the implementation of these steps, it is quite apparent that the consultants have not been able to improve the assembly line as much as desired by the company.