# 11 - Statistics

## Percentage

To calculate a percentage, we divide the number by the total number and we multiply the result by 100.

(If we just do , the result is called the frequency).

If in a class there are 9 handsome boys and 6 boys that are less handsome, since , this means that there are 60% of the boys in the class who are handsome (There will not be enough for everybody).
If a tennis player serves 90 first serves and is successful with 28 of them, his percentage of first ball is 31%.
If a pie weighs 500g and Mary eats 80g of it, she will have eaten 16% of the pie. You can verify these results with the help of the formula to calculate percentages.

## Mean

To calculate a mean, we add all the values and we divide the result by the number of values. If you had 6, 4, 8, 5, 4, 9 at your math exams and after having read this site you get 16, your mean mark for math will be .

## Accumulated numbers

 Match againstChicago bullsNew Orlean HornetsDenver NuggetsDetroit PistonsPhoenix SunsLos angeles LakersSeattle SupersonicsHouston Rockets Score from San Antonio Spurs :861057995101998068 Accumulated number86191270365466565645713

To calculate the column of accumulated numbers, we add the new value each time.