Question

calculate arithmetic mean of the following data (x) 20 30 40 50 60 70 and frequency (f) 8 12 20 10 6 4.​

Answer 1

Answer:

Marks(I) 10-20-30-40-50-60-70-

20 30 40 50 60 70 80

xi 15 25 35 45 55 65 75

fi 3 7 10 6 8 2 4

fixi 45 175 350 270 440 130 300

x= Fixi 1710

fi = 40 = 42.75

Answer 2

Given:

We are given the following data shown in the table:

  $\left[\begin{array}{ccccccc}x&20&30&40&50&60&70\\f&8&12&20&10&6&4\end{array}\right]$

To FInd:

Arithmetic mean of the above data.

Solution:

The arithmetic mean (AM) can be defined as the ratio of the sum of all the observations to the total number of observations.

The arithmetic mean of a given ungrouped data can be found using the formula  

          $AM=$∑$fx$$/$∑$f$

Where $x$ is the data and $f$ is its respective frequency.

         $AM=\frac{20*8+30*12+40*20+50*10+60*6+70*4}{8+12+20+10+6+4}$

                 $=\frac{2460}{60}$

                 $=41$

Hence, the arithmetic mean of the given data is 41.