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=162


                   Total number of observations \Sigma f_i=20


                         So, the mean = \frac{162}{20}


                               Mean = 8.1

                 Hence mean number of plants per house is 8.1.