arises during the "cross-multiplication" phase. For instance, in a common version of this problem where the mean is 25358253 over 58 end-fraction The total sum of scores ( ∑fixisum of f sub i x sub i ) is calculated as The total number of pupils ( ∑fisum of f sub i The equation becomes: When you cross-multiply , the first term you get is . 3. Step-by-Step Resolution Expand the sides : Isolate : Simplify : Final Result : In the context of statistical distribution homework, 5278x5278 x is the product of , used to solve for the variable

, you must set up an equation using the formula for the mean (

In these problems, you are often given a frequency distribution of scores where the number of pupils is expressed in terms of , etc.). To find the value of