Krishna
0

Step 1: Recall the formula of the mean of the grouped data

            NOTE: The mean (or average) of observations is the sum of the values of

            all the observations divided by the total number of observations.


            Let x_1, x_2, x_3............, x_n be observations with respective

             frequencies f_1, f_2,............f_n


                   Mean = \frac{f_1x_1 + f_2x_2 + ........f_nx_n}{f_1 + f_2 +..........+ f_n}

                                   or


                        Mean = \frac{\Sigma f_ix_i}{\Sigma f_i}


Step 2: Re-organize given data in the table and find the sum of all observations.


                        


                  Sum of the values of all the observations \Sigma f_ix_i = 2.96


                     Total number of observations \Sigma f_i=30


                      So, the mean = \frac{2.96}{30}


                                 Mean = 0.099 ppm