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 disk drive (HDD) is a hardware device that's used to store information like software and files. The primary hard disk in a PC is the C drive.