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.
hard disk drive (HDD) A computer hard disk drive (HDD) is the mechanism that controls the positioning, reading and writing of the hard disk, which furnishes data storage. A hard disk drive -- often shortened to hard drive -- and hard disk are not the same thing, but they are packaged as a unit and either term can refer to the whole unit. Hard disk drives can be found in desktop computers, mobile devices, consumer electronics and enterprise storage arrays in data centers.