Page 209 - Data Science class 10
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7.  Mohan has rupees notes  of different denominations. He noted down the number of notes  of various
                  denominations in a table as follows:
                       Marks        10    20    50   100   500   2000

                    No. of Notes    20    40    30    10    50    60
                  Calculate the mode of the above data.
              Ans.  Notice that 2000 rupee note has highest number. So, the mode is 2000.



               8.  Create a frequency table for the following:

                    12       5     4     3     8      9   12       9     8      7
                      6    71    12    30      2      5      4     3   71       8
                      7    12      9     6     4      2      1   71    22       3
                    22     12      8     9     5    12       4     3   12     71


              Ans.   12      5     4     3     8      9   12       9     8     7
                      6   71     12    30      2      5     4      3   71      8
                      7   12       9     6     4      2     1    71    22      3
                    22    12       8     9     5    12      4      3   12    71
                  Element        Tally          Frequency

                   1             /              1
                   2             //             2
                   3             ////           4
                   4             ////           4
                   5             ///            3

                   6             //             3
                   7             //             2
                   8             ////           4
                   9             ////           4
                  12             //// //        7
                  22             //             2
                  30             /              1

                  71             ////           4
               9.  Find the population variance of the following dataset:
                  3, 5, 5, 6, 6, 7, 8, 10, 10, 10, 12, 15, 20
              Ans.  Find the mean by adding all data values and divide by the sample size n.
                          (3 + 5 + 5 + 6 + 6 + 7 + 8 + 10 + 10 + 10 + 12 + 15 + 20)
                  Mean =
                                                    13
                        = 9
                  The population variance is:
                                                         2 ∑   n  ( x  –  ) m  2
                                                       s =     i= 1  1
                                                                  n

                                                                                   2


                                                                   2
                                                                           2



                                                                                                           2


                                                                                                   2


                                                                                           2






                                       2
                                2
                         2







                                                            2
                                                     2
                                              2


                  =  (3–9) +(5–9) +(5–9) +(6–9) +(6–9) +(7–9) +(8–9) +(10–9) +(10–9) +(10–9) +(12–9) +(15–9) +(20–9) 2
                                                                   13
                                                                                          Practical Questions  207
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