The content of 100 match boxes were checked to detemine the number of matches they contained .
|no of matches||35||36||37||38||39||40||41|
|no of boxes||6||10||18||25||21||12||8|
(1) Calculate, correct to one decimal place, the means number of matches per box .
(2) Determine how many extra matches would have to be added to the the total contents of the total content of the 100 boxes to bring the mean up to exactly 39 matches.
|No of matches (x)||No.of boxes (F)||fx|
(1)`barx=(∑ fx )/(∑f)=3813/100=38.13`
(2) In the second case ,
New mean = 39 matches
Total contents =39 x 100 = 3900
But total number of matches already give = 3813
Number of new matches to be added = 3900 - 3813 = 87