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 relay is an electrically operated switch. Many relays use an electromagnet to mechanically operate a switch, but other operating principles are also used, such as solid-state relays. Relays are used where it is necessary to control a circuit by a separate low-power signal, or where several circuits must be controlled by one signal.
Interposing Relay is the auxiliary relay which is used to isolate the two different systems/ devices. This could be because they have different 0V references, different voltages, AC vs. DC. For example, let's say the relay of a PLC can only avail 1 A at 110 VAC, but the Controller which is to be connected to the relay requires 1.5 A at 110 VAC.