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5.  In a manufacturing company, the number of employees in unit A is 40, the mean is ` 6400 and the number of employees
              in unit B is 30 with the mean ` 5500 then the combined arithmetic mean is :
          Ans.  In unit A, there are 40 employees with average of ` 6400
               So, total quantity shall be = 40 × 6400 =256000.
               In unit B there are 30 employees with average of ` 5500
               So, total quantity shall be = 30 × 5500 = 165000.
               Total amount shall be 256000 + 165000 = ` 421000.
               Total employees are 40 + 30 = 70.
               So let us divide these two to get the combined mean.

               Thus the combined mean =   421000   = 6014.29 (aproximately).
                                         70


                                                 Unsolved Exercise



             Objective Type Questions (Section A)


        A.  Tick ( ) the correct option.
            1.  The square root of the variance is called the ____________________.
              a.  empirical                                      b.  mean
              c.  mode                                           d.  standard deviation

            2.  The mean absolute deviation is divided by coefficient of mean absolute deviation to
              calculate ____________________.                                                     [CBSE Handbook]
              a.  Variance                                       b.  Median
              c.  Arithmetic Mean                                d.  Coefficient of Variation
            3.  The  most recurrent value in the sample set is known as ____________________.
              a.  Mean                                           b.  Median

              c.  Mode                                           d.  Standard Deviation
            4.  What is the median of the following dataset?
               10, 30, 40, 20, 40, 50, 40, 40, 50, 60, 60, 70, 80, 50
              a.  45                                             b.  40
              c.  50                                             d.  45.71

            5.  Find the wrong statement.
              a.  A random variable is a numerical outcome of an experiment
              b.  Continuous random variable can take any value on the real line
              c.  There are three types of random variable
              d.  None of the above

            6.  Find the mean of the following data:
               9, 7, 11, 13, 2, 4, 5, 5
              a.  8                                              b.  10
              c.  6                                              d.  7

            7.  Which is a more accurate measure of central tendency when there are outliers in the dataset?   [CBSE Handbook]
              a.  Mean                                           b.  Median
              c.  Mode                                           d.  Variance
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