Finding Arithmetic mean of this given data

[aws02]

The task is to find the Arithmetic mean of this data. I think it should be as follows line 1 for example (100+150)/2 * 14
line 2: (150+200)/2 * 18 then sum all the results and divide them be the number of days which is 144. What do you think?

 

[JeffM]

The task is to find the Arithmetic mean of this data. I think it should be as follows line 1 for example (100+150)/2 * 14
line 2: (150+200)/2 * 18 then sum all the results and divide them be the number of days which is 144. What do you think? View attachment 3524

Your thinking is good. You do realize, however, that what you are calculating is the approximate weighted mean by assuming that each instance in a class is the midpoint of the class. Nothing wrong with that; good thinking, but I'd be happier if the problem had said approximate mean.

 

[Lexadis]

Well what I have learnt in my school is to create an additional mid value (x) column, fx column and find the mean by the equation : $\displaystyle \frac{\sum fx}{\sum f}$