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第 2 章 : 數據的基本概念 Basic Concepts on Data

第 2 章 : 數據的基本概念 Basic Concepts on Data. S.4-5 CS&IT CE Course 中四及中五電腦與資訊科技會考課程. 數據和信息 Data and Information. 數據 Data ：. 是各式各樣 未經組織 及 沒有意義 的事實 Consists of all sorts of unorganised and meaningless facts 可以是 數字 、 字符 或 圖形 numbers , characters or graphics.

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第 2 章 : 數據的基本概念 Basic Concepts on Data

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  1. 第 2 章 : 數據的基本概念Basic Concepts on Data S.4-5 CS&IT CE Course 中四及中五電腦與資訊科技會考課程 CUHK FAA Thomas Cheung Sec Sch

  2. 數據和信息 Data and Information 數據 Data： • 是各式各樣未經組織及沒有意義的事實 Consists of all sorts ofunorganisedand meaningless facts • 可以是數字、字符或圖形numbers, characters or graphics CUHK FAA Thomas Cheung Sec Sch

  3. 數據和信息 Data and Information • 信息Information • 則是一些經過處理、有用及有意義的數據 Is processed data which is meaningfuland useful CUHK FAA Thomas Cheung Sec Sch

  4. 數據和信息 Data and Information • 把原始數據轉化成有用信息的過程，稱為數據處理 • The process of converting raw data into meaningful information is known as data processing 數據 Data 處理 Processing 信息 Information CUHK FAA Thomas Cheung Sec Sch

  5. 數據收集和準備Data Collection and Data 數據可以透過不同的方式取得 Data can be obtained in different ways： • By interviews, questionnaires and forms 訪問、問卷和表格 CUHK FAA Thomas Cheung Sec Sch

  6. 2. 觀察和測量 By Observations and Measurements CUHK FAA Thomas Cheung Sec Sch

  7. 3. 實驗 By Experiments CUHK FAA Thomas Cheung Sec Sch

  8. 數據的收集和準備 Data Collection and Data • 檢查數據的準確性 Checking data for accuracy • 重組數據 Structuring data CUHK FAA Thomas Cheung Sec Sch

  9. 檢查數據的準確性 Checking data for accuracy • 例如：需要檢查填妥的問卷內的資料，看看是否有遺漏、文化上的錯誤 eg. a filled-out questionnaire needs to be edited for missed-out data, spelling or grammatical mistakes CUHK FAA Thomas Cheung Sec Sch

  10. 重組數據Structuring data • 把數據重組為方便輸入至電腦的形式Rearranging data in a form that facilitates data input CUHK FAA Thomas Cheung Sec Sch

  11. 數據管理 Data Management 錯誤的來源 Sources of Errors • 收集數據階段 During data collection • 準備數據階段 During data preparation • 輸入數據階段 During data input • 處理數據階段 During data processing • 輸出信息階段 During informationoutput CUHK FAA Thomas Cheung Sec Sch

  12. 錯誤的來源 Sources of Errors • 收集數據階段 During data collection CUHK FAA Thomas Cheung Sec Sch

  13. 錯誤的來源 Sources of Errors • 準備數據階段 During data preparation 舉例：為源文件進行編輯時，有可能誤將「8」字誤寫為「3」 Eg. writing a “3” for an “8”when preparing an edited version of the source document CUHK FAA Thomas Cheung Sec Sch

  14. 錯誤的來源 Sources of Errors 輸入數據時，操作員可能會錯誤鍵入、誤讀或遺漏數據，因而做成錯誤 When data are inputted into a computer, errors may occur if the operator makes typing mistakes, misreador even leaves out the data • 輸入數據階段 During data input CUHK FAA Thomas Cheung Sec Sch

  15. 錯誤的來源 Sources of Errors • 處理數據階段 During data processing 不正確的電腦程序或處理步驟 May come from incorrect programs or procedures CUHK FAA Thomas Cheung Sec Sch

  16. 錯誤的來源 Sources of Errors • 輸出信息階段 During information output 使用了有問題的輸出設備 May be produced by a defectiveoutput device CUHK FAA Thomas Cheung Sec Sch

  17. 數據控制 Data Control 數據控制是為確保輸入數據的準確性和完整性的措施 Data controlrefers to the measures to ensure that the data inputted is accurate and complete CUHK FAA Thomas Cheung Sec Sch

  18. 數據控制 Data Control • 數據校驗Data verification • 數據有效性檢驗Data validation CUHK FAA Thomas Cheung Sec Sch

  19. 數據校驗Data Verification • 檢查輸入的數據與源文件的數據是否一致 Checking of the truth or accuracy of data CUHK FAA Thomas Cheung Sec Sch

  20. 數據校驗Data Verification • 輸入的數據會即時輸出，並跟源文件比較以作檢查 Data items entered are outputted immediately for checking CUHK FAA Thomas Cheung Sec Sch

  21. 數據校驗Data Verification • 相同的數據會由兩名操作員獨立地輸入 Data items are typed into a computer by two different operatorsindependently CUHK FAA Thomas Cheung Sec Sch

  22. 數據有效性檢驗Data Validation • 數據有效性指輸入的數據是合理和可接受的 Refers to the data inputted being acceptable and reasonable CUHK FAA Thomas Cheung Sec Sch

  23. 數據有效性檢驗的種類 Type of Data validation • 類型檢查 Type check • 範圍檢查 Range check • 長度檢查Length check • 合理性檢查 Reasonableness check • 數位檢查Check Digit CUHK FAA Thomas Cheung Sec Sch

  24. 類型檢查Type Check • 例如考試分數應該是數字而不會是文字 e.g. examination marks should be numbersbut not alphabets CUHK FAA Thomas Cheung Sec Sch

  25. 範圍檢查 Range Check • 例如一月的日數應在 1 至 31 之內 e.g. the number of days in January should be within 1 – 31 CUHK FAA Thomas Cheung Sec Sch

  26. 長度檢查 Length Check • 例如香港的電話號碼通常是由 8 個數位所組成的 A telephone number in Hong Kong has 8 digits CUHK FAA Thomas Cheung Sec Sch

  27. 合理性檢 Reasonableness Check • 例如一個 200 公斤的 5 歲孩子是很不合理的 e.g. a 5-year-old child having a weight of 200 kg is incredible CUHK FAA Thomas Cheung Sec Sch

  28. 檢查數位 Check Digit • 是附加在某個代碼末尾處的一個數位，在身分證號碼或國際標準書號中都可以找到 An extra digit at the end of a code, e.g. Identity Card Number, International Standard Book Number (ISBN) CUHK FAA Thomas Cheung Sec Sch

  29. 數據在電腦內的表示方式Representation of Data inside a Computer 十進制、二進制及十六進制數系 Denary, Binary and Hexadecimal Number Systems • 十進制數系 Denary number system • 以0、1、2、3、4、5、6、7、8、9 • 十進制數 419210的展開式為： 即419210 = 4×103+ 1×102 + 9×101 + 2×100 CUHK FAA Thomas Cheung Sec Sch

  30. 十進制小數 0.21310的展開式為： 十進制數系 Denary Number System 即0.21310 = 2×10-1+ 1×10-2 + 3×10-3 CUHK FAA Thomas Cheung Sec Sch

  31. 二進制數系 Binary Number System • 只以 0 和 1 兩個數字來表示數 only digits 0 and 1 are used 數系的底數是2 a base-2 number system • 二進制數 11112 的展開式為 a binary number 11112 in expanded form is: 即 11112 = 1×23+ 1×22 + 1×21 + 1×20 CUHK FAA Thomas Cheung Sec Sch

  32. 二進制小數系 Binary Fraction Number System • 二進制小數 0.10112 的展開式為： • a binary fraction 0.10112 in expanded form is: 即0.10112 = 1×2-1+ 0×2-2 + 1×2-3 + 1×2-4 CUHK FAA Thomas Cheung Sec Sch

  33. 十六進制數系 Hexadecimal Number System 0、1、2、3、4、5、6、7、8、9、A、B、C、D、E、F A = 10 B = 11 C = 12 D = 13 E = 14 F = 15 CUHK FAA Thomas Cheung Sec Sch

  34. 十六進制數系 Hexadecimal Number System • 十六進制數 2C3D16的展開式為： • Hex. number 2C3D16 in expanded form is: 即 2C3D16 = 2×163+ C×162 + 3×161 + D×160 CUHK FAA Thomas Cheung Sec Sch

  35. 使用二進制數字表示數據 Using Binary Digits to Represent Data • 在電腦內，數據會以二進制數「0」和「1」表示 In a computer, data are represented by binary digits 0 and 1 • 美國信息交換標準碼 American Standard Code for Information Interchange (ASCII) • 目前最普及的字符編碼系統 the most popular coding system for characters • 使用一個字節作為編碼來表示每個字符 uses a byte as a code to represent each character CUHK FAA Thomas Cheung Sec Sch

  36. 使用二進制數字表示數據 Using Binary Digits to Represent Data • 要表示中文字符，每個中文字編配一個16位的「內碼」 To represent Chinese characters, each Chinese character is assigned a 16 bits “internal code” CUHK FAA Thomas Cheung Sec Sch

  37. 堂課 Classwork • P.29 MC Q.1-7 • P.31 Q.5, 6 CUHK FAA Thomas Cheung Sec Sch

  38. 功課 Homework • P.30 Q.1-4, 7 CUHK FAA Thomas Cheung Sec Sch

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