Page 195 - Math Course 3 (Book 2)
P. 195

Sampling and Bias




                          Systematic random sample                 Your Turn!
                       Definition             Examples
                 In a systematic random  Every 2 minutes, an item   Classify a Random Sample
                  sample, the items are     is pulled off the
                 selected according to a   assembly line or        At an automobile factory, every tenth item is
                  specified time or item                           checked for quality controls. Identify the sam-
                        interval.        Every twentieth item is   ple and suggest a population from which it was
                                        pulled off the assembly    selected.
                                                 line.
                                                                   A. The sample is every tenth item. The population
                                                                        is all of the products that are manufactured in
                                                                        the factory.
                             Let’s Begin
                                                                   B. The sample is all products that are
                                                                        manufactured in the factory. The population is
                                                                        every tenth item.
               Classify a Random Sample
                                                                   C. The sample is a car. The population is all cars.
                   Example                                         D. The sample is unbiased. The population is all
                                                                        cars.

                RETAIL
                Each day, a department store chain selects one       Answer
                male and one female shopper randomly from each
                of their 57 stores and asks them survey questions   At an automobile factory, every tenth item is
                about their shopping habits.                       checked for quality controls. Classify the sample
                                                                   as simple, stratified or systematic.
                                                                   A. simple random sample
                                                                   B. stratified random sample
                                                                   C. systematic random sample
                                                                   D. none of the above


                                                                     Answer







                Identify the sample and suggest a population from
                which it was selected.

                                The sample is 57 male and 57
                                female shoppers each day. The
                   Answer
                                 population is shoppers in the
                                       chain’s stores.

                             Classify the sample as
                         simple, stratified, or systematic.

                      The population is divided into similar,
                            nonoverlapping groups.




                   Answer     This is a stratified random sample.



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