1. Data Collection Methods

2. After choosing a sampling method, we need to collect data from the sample selected. Can you name some data collection methods that learnt in junior forms? 1.Observation 2.Interview 3.Questionnaire 4.Experiment Data collected from these methods are called primary data.

3. Advantages and disadvantages of the 4 data collection methods: Data collection method AdvantagesDisadvantages ObservationSimple and flexible Can be combined with other methods No realistic when the sample size is large InterviewHigher response rate Gather more details on items of particular interest and ask follow-up questions High cost and large manpower Inappropriate for collecting sensitive data Slow QuestionnaireUseful with large samples Can collect sensitive data Requires less cost and manpower Low response rate Questionnaire have to be carefully designed ExperimentCan collect data about the effect of a certain factor on another May be time consuming and costly May be influenced by factors

4. Besides the above four methods, we can also collect data from…… 1.Official statistical publications 2.Electronic encyclopedias 3.the Internet, etc Data collected from these methods are called secondary data.

5. Follow-up question Can you give an example of a survey for each of the following data collection methods: observation, interview, questionnaire, experiment?