An Alternative Definition for IQR. In some texts, the interquartile range is defined differently. It is defined as the difference between the largest and smallest values in the middle 50% of a set of data. To compute an interquartile range using this definition, first remove observations from the lower quartile.
A hard drive is a device used to store data in a semipermanent state on your computer. Computer memory is a series of small packets of data called bits. Each bit is a 1 or a 0, and each bit is stored as a small magnetic charge on the hard drive. A read/write head moves over the hard drive to retrieve or rewrite the bits as needed.
A hard drive is nothing more than a magnetised storage area. Your Operating System is stored on your hard drive, as well as all your software programmes, like Microsoft Word. The hard drive is actually a few circular disks stacked one on top of the other. A little arm moves over the disks and writes things to these circular platters, and reads them.