Attractive nuisances can create liability risks. Learn what a home attractive nuisance is and see the most common attractive nuisance examples.
In mathematics, the harmonic mean (sometimes called the subcontrary mean) is one of several kinds of average, and in particular one of the Pythagorean means. Typically, it is appropriate for situations when the average of rates is desired. The harmonic mean can be expressed as the reciprocal of the arithmetic mean of the reciprocals. As a simple example, the harmonic mean of 1, 2, and 4 is 3 1 1 + 1 2 + 1 4 = 1 1 3 ( 1 1 + 1 2 + 1 4 ) = 12 7 .
The harmonic mean is a better average when the numbers are defined in relation to some unit. The common example is averaging speed. For example, suppose that you have four 10 km segments to your automobile trip. You drive your car: 1  100 km/hr for the first 10 km. 2  110 km/hr for the second 10 km.