How To Get The Average Of Two Percentages?


3 Answers

Josh H Profile
Josh H answered
Its the same as finding average of numbers. Turn % into decimal (like 78.8% into .788) add the %'s up and divide by # of percentages. Ex: 50%, 30%, 26%... .5+.3+.26=.96...divide by 3. .96/3=.32...average is .32 or 32%
thanked the writer.
Oddman commented
You don't have to go to the trouble of converting to decimals and back. You can average the percentages directly: Average[40%,20%] = ((40+20)/2)% = 30%.

Since a % is a unitless number, one wonders why anybody would want to average them. Quite often, the math will only be meaningful if the underlying numbers, not the percents, are averaged.
Oddman Profile
Oddman answered
Your question does not make sense. It can be interpreted a couple of ways.  The average of a group of percentages can be calculated according to any formula that you wish. A percentage is a ratio. It usually does not make sense to average ratios, unless they all have the same base number or the same weighting. (Yes, this is often done in school, where percentage grades on tests are averaged. Giving a 2-question quiz the same weight in an average as a 50-question quiz seems unfair to me.)) The usual formula for an average is   average = (sum of numbers)/(number of numbers)  The percentage of an average can be defined, too. A percentage of any number is the product of the number and the percentage. Recognize that a percentage can be expressed as a ratio (or fraction) or a decimal number, if those are more convenient for your calculation. Many people do not need to convert 10% to any other form in order to recognize that multiplying by it means moving the decimal point one place to the left, for example.

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