A proportion multiplied by 100; SYN. percent, per centum, pct.
Way of representing a number as a fraction of 100. Thus 45 percent (45%) equals 45/100, and 45% of 20 is 45/100 x 20 = 9.
In general, if a quantity x changes to y, the percentage change is 100(x - y)/x. Thus, if the number of people in a room changes from 40 to 50, the percentage increase is (100 x 10)/40 = 25%. To express a fraction as a percentage, its denominator must first be converted to 100— for example, 1/8 = 12.5/100 = 12.5%. The use of percentages often makes it easier to compare fractions that do not have a common denominator.
The percentage sign is thought to have been derived as an economy measure when recording in the old counting houses; writing in the numeric symbol for 25/100 of a cargo would take two lines of parchment, and hence the “100” denominator was put alongside the 25 and rearranged to “%”.
In a cumulative frequency distribution, one of the 99 values of a variable that divide its distribution into 100 parts of equal frequency. In practice, only certain of the percentiles are used. They are the median (or 50th percentile), the lower and the upper quartiles (respectively, the 25th and 75th percentiles), the 10th percentile which cuts off the bottom 10% of a frequency distribution, and the 90th which cuts off the top 10%. The 5th and 95th are also sometimes used.
ETYM Old Fren., from Latin rata (sc. pars), from ratus reckoned, fixed by calculation, p. p. of reri to reckon, to calculate. Related to Reason.
1. Amount of a charge or payment relative to some basis; SYN. charge per unit.
2. A magnitude or frequency relative to a time unit.
3. (British) A local tax on property (usually used in the plural).