Secondary data , Using data collected previously by someone else from sources such as online website and books, Primary Data , Data collected for the first-time using tools such as interviews and survey's, Bias , The data source is using unethical and unfair practices of getting data., Size , The sample size must be enough for the data to be valid , Reputation , The sources of data must have good reputation on relevant subjects..

排行榜

視覺風格

選項

切換範本

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恢復自動保存: ?