# Math Is Fun Forum

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## #1 2021-12-05 10:23:30

Hannibal lecter
Member
Registered: 2016-02-11
Posts: 330

### percentage point

Hi, I find in math is fun site on this link talking about percentage point :

https://www.mathsisfun.com/percentage-points.html

in start the site said :

Example: Your earnings per sale went from 4% to 5%
That is a rise of 1 Percentage Point

(But is a 25% rise in your earnings!)

but I didn't find an live example may you make to me an example
like I'm selling a laptop by 100\$ or any small little example explain how I'll be earn rising 25%!

Wisdom is a tree which grows in the heart and fruits on the tongue

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## #2 2021-12-05 11:29:30

Hannibal lecter
Member
Registered: 2016-02-11
Posts: 330

### Re: percentage point

in Wikipedia it said :
percentage point or percent point is the unit for the arithmetic difference of two percentages. For example, moving up from 40 percent to 44 percent is an increase of 4 percentage points, but a 10-percent increase in the quantity being measured
I notice it said " but a 10-percent increase in the quantity being measured"
is there a simple example to explain that in real life time

Wisdom is a tree which grows in the heart and fruits on the tongue

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## #3 2021-12-06 00:45:08

Bob
Registered: 2010-06-20
Posts: 9,358

### Re: percentage point

hi,

If you have the actual earnings of an employee; or the figures for the number of a rare species; or the cost of a new Tv; then you know some raw data.

But sometimes a statistician will compute a number from the data such as an average; or a percentage increase.  Such a number is called a statistic.  These can be useful but they can also be used to mislead. In the 19th century the politician Benjamin Disreali said "There are lies, darn lies and statistics."  Darrell Huff wrote a humorous book  called How to Lie with Statistics.  The lesson to learn from this is that statistics can be a tricky area and misuse can give very different answers.

Let's look at an example.  An ornithologist (bird lover) might be collecting data on how many birds in a species have an unusual coloration.  Each year, he records the numbers and graphs the percentage that have the unusual coloration, year by year.  If the percentage has gone up from 4% to 5% in successive years then you could say that's an increase in that proportion of 1%.  But, as you have noticed, an increase from 4 to 5 is correctly a 25% increase.  Both are correct, if you understand what statistic is being calculated

I'd like to know the raw data.  If the total in the species has gone down then the 'increase' might not have much significance.

Confusing? Well yes, but whenever you are told a statistic you ought to be questioning what calculation has taken place and what it means.

Let's have another example.  The boss of a small company announces  that the company is doing so well that everybody is going to get a 10% pay rise.  The workers think great!  They were getting \$200 a week.  Now they'll get \$220.  That's an extra \$20 to spend (I'll ignore Uncle Sam for now)

But the union leader has a different picture to paint.  He knows that the boss used to take \$10000 a week from the company and that he intends to give himself the same pay rise; 10% on \$10000 is another \$1000!  So the union guy argues that the workers are only getting 20/1000 x 100% or 2% of the pay rise that the boss is getting.  This is what Disreali meant by statistical lies. Depending what stats you perform you can create very different statistics to support your case.

Just make sure you understand what has been calculated and if a question asks you to calculate a percentage, make sure you are clear about the before, the after and how you are expected to calculate the %

Usually

The problem with the example you found is that 4% and 5% are already percentages so calculating a percentage from these is a tricky thing to do.

Bob

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

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## #4 2021-12-06 03:23:41

Hannibal lecter
Member
Registered: 2016-02-11
Posts: 330

### Re: percentage point

Bob wrote:

Let's have another example.  The boss of a small company announces  that the company is doing so well that everybody is going to get a 10% pay rise.  The workers think great!  They were getting \$200 a week.  Now they'll get \$220.  That's an extra \$20 to spend (I'll ignore Uncle Sam for now)

Bob

the increase here is 10% as mention because 10% of 200 is 20 that's a percent increase right
but what is the percentage point here?

Wisdom is a tree which grows in the heart and fruits on the tongue

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## #5 2021-12-06 22:57:25

Bob
Registered: 2010-06-20
Posts: 9,358

### Re: percentage point

I just made up an example to show how you can use statistics to give very different messages by calculating in different ways.  There isn't any percentage point data because the pay rise was a one off event.

B

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

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