questions","basePath":"/gcse/computer-science/aqa/data-compression/questions","formulaUrl":null,"initialIndex":29,"initialQuestionWindow":[{"id":"66308f2d-056a-4bfa-ac70-4d1a03b4b555","revisionId":"3c98e71a-6441-487f-af22-39bd46f99ab0","questionNumber":null,"questionType":"LA","specification":"","difficulty":3,"difficultyBand":"easy","totalMarks":2,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"d23a4177-e830-4163-bdd1-78cf4c226b19","label":null,"content":"When a Huffman tree is used, the string in Figure 1 can be represented using 138 bits.\n\n### Figure 1\n`ARTIFICIAL INTELLIGENCE ALGORITHM`\n\nThe 33-character string shown in Figure 1 could also be encoded using standard 8-bit ASCII.\n\nHow many bits are saved when Huffman coding is used rather than ASCII to represent the string shown in Figure 1?\n\nYou must show your working.","markscheme":"- Calculates the ASCII bit size correctly by multiplying 33 characters by 8 bits to get $264$ bits M1\n- Subtracts 138 bits from their calculated ASCII bit size to find a saving of $126$ bits (or correctly subtracts 138 from an incorrect ASCII product) A1","marks":2,"order":0,"markingRubric":null,"explanation":null,"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"678319ec-8323-4fb0-9822-ffa1ffddd3b7","revisionId":"f698d481-52da-4f01-ae50-1dab65896f74","questionNumber":null,"questionType":"LA","specification":"","difficulty":3,"difficultyBand":"easy","totalMarks":3,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"3a3114f4-766e-401e-92fd-6ef4138c5b6c","label":null,"content":"Complete the code table below for characters O, N, and G using the Huffman tree shown in Figure 1. The binary code for character S has been filled in as an example.\n\n![Figure 1: Huffman tree for characters S, O, N, and G](https://assets.mathsgenie.co.uk/aqa-qb/16533544-d1b3-40c6-9243-f1072b135af9.png)\n\n| Character | Binary code |\n| :--- | :--- |\n| S | 1 |\n| O | |\n| N | |\n| G | |","markscheme":"- Traces the tree to find the correct binary code for O as $00$ B1\n- Traces the tree to find the correct binary code for N as $010$ B1\n- Traces the tree to find the correct binary code for G as $011$ B1","marks":3,"order":0,"markingRubric":null,"explanation":null,"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"6d3f5f4c-fdcf-44bc-ae19-7a7b3ff395b1","revisionId":"3d0bc114-ab64-455e-a401-d6e79aaa5f91","questionNumber":null,"questionType":"LA","specification":"A telemetry subsystem on a meteorological station encodes status data using a Huffman code. The Huffman tree shown below is generated from a sequence of status logs.\n\n![Huffman tree for sensor status data](https://assets.mathsgenie.co.uk/aqa-qb/2f6077cb-2bc9-46cb-8a92-357a1c7ace82.png)","difficulty":3,"difficultyBand":"easy","totalMarks":1,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"ae882a0e-c94c-4c95-91aa-be7ca2e39c8a","label":null,"content":"Determine the string represented by the binary sequence `0111000010011`.","markscheme":"- Decodes the binary sequence step-by-step:\n * `011` $\\rightarrow$ **S**\n * `100` $\\rightarrow$ **T**\n * `00` $\\rightarrow$ **A**\n * `100` $\\rightarrow$ **T**\n * `11` $\\rightarrow$ **E**\n to give the final decoded string **STATE** A1","marks":1,"order":0,"markingRubric":null,"explanation":null,"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null}],"subjectCode":"gcse_computer_science__aqa","summaries":[{"id":"01aceeda-575c-4ced-bc96-ba092de79c7e","difficultyBand":"medium","calculatorUse":null},{"id":"03fe5cea-6efd-45d9-aa60-75964ab4705a","difficultyBand":"easy","calculatorUse":null},{"id":"07d36a1a-5c14-476d-80ea-f2079e422bfb","difficultyBand":"easy","calculatorUse":null},{"id":"0ab264e5-e293-4736-91b6-fd500dfb6b02","difficultyBand":"easy","calculatorUse":null},{"id":"0fc37e4c-7cae-4c1a-9fb3-66f966107332","difficultyBand":"medium","calculatorUse":null},{"id":"1cb71686-bddf-4766-bac7-646e97cdb718","difficulty

Data compression

Question 16

Data compression Questions

Data compression

Question 16

Data compression Questions