Page 177 - Data Science class 10
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5.  What is sampling error? Write the formula to calculate it.
             Ans.  A sampling error is a deviation in the sampled value versus the true population value. Because the sample is not typical
                  of the population or is skewed in some manner, sampling mistakes happen. Even randomised samples will have some
                  degree of sampling error because a sample is only an approximation of the population from which it is drawn.
                  The formula of Sampling Error is as follows:
                                                      Sampling Error Z =   s
                                                                        n
               6.  How can you calculate the Sampling Error of the sample size equal to 100 of the total strength with a standard deviation
                  equal to 0.5 at 90% confidence level?
             Ans.  s = 0.5
                  n = 100
                  The value of z at 90% of confidence level = 1.645

                  Sampling error =   0.5   × 1.645
                                  100
                               =   0.5   × 1.645 = 0.08225
                                   10
               7.  A puzzle game has 38 columns – 18 blue, 18 orange and 2 yellow columns.  Swati plays five games and always bets on
                  orange columns. What is the probability of the number of games she can win?
                  a.  1.1165
                  b.  2.3684
                  c.  2.6316
                  d.  4.7368
             Ans.   The probability that the appearing column will be orange is   18  .
                                                                    38
                  Now Swati is playing the game 5 times and all the games are independent of each other.
                  Thus, the number of games that she can win would be 5 ×   18   = 2.3684
                                                                   38


                                                     Unsolved Exercise




                 Objective Type Questions (Section A)


            A.  Tick ( ) the correct option.
               1.  Which of the following is NOT a type of bias?                                     [CBSE Handbook]
                  a.  Selection Bias                                 b.  Linearity Bias

                  c.  Recall Bias                                    d.  Trial Bias
               2.  Based on a statistic calculated from a sample randomly selected from the population, ____________________ allow you to
                  make a well-informed forecast about a population parameter.
                  a.  inferential statistics                         b.  probability
                  c.  statistical equation                           d.  None of these

               3.  Sample of size 25 are selected from a population with mean 40 and standard deviation 7.5. The mean of the sampling
                  distribution sample mean is ____________________.
                  a.  7.5                                            b.  8
                  c.  40                                             d.  5.5


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