// Numbas version: finer_feedback_settings
{"name": "SA12  Interpret contingency table", "extensions": ["stats"], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"name": "SA12  Interpret contingency table", "tags": [], "metadata": {"description": "<p>Calculate an intersection probability given a two way table.</p>", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "", "advice": "<p>a) Each row and column must sum to the 'total'.</p>\n<p>b) Look for the column containing '$\\var{q1a}$' and the row containing '$\\var{q1b}$'. &nbsp;The entry where they intersect, $\\var{q1*total}$, is&nbsp;the value we are interested in. &nbsp;<br/><br/>Since we require a probability, this is $\\var{q1*total}$ out of $\\var{total}$, i.e.<br/><br/></p>\n<p>\\[ \\frac{\\var{q1*total}}{\\var{total}} \\]</p>\n<p></p>\n<p style=\"text-align: center;\"><a href=\"https://www.sheffield.ac.uk/mash/stats-resources/first-steps#contingency-tables\" target=\"_blank\" rel=\"noopener\">Use this link to find some resources which will help you revise this topic</a></p>", "rulesets": {}, "extensions": ["stats"], "builtin_constants": {"e": true, "pi,\u03c0": true, "i": true}, "constants": [], "variables": {"nA": {"name": "nA", "group": "Final data", "definition": "pairs[0]", "description": "", "templateType": "anything", "can_override": false}, "pairs": {"name": "pairs", "group": "Final data", "definition": "random(['red','shiny'],['Phenotype A','Phenotype B'],['dairy', 'wheat'],['F','G'],['child','dog owner'],['X','Y'],['hat', 'glasses'])", "description": "", "templateType": "anything", "can_override": false}, "nB": {"name": "nB", "group": "Final data", "definition": "pairs[1]", "description": "", "templateType": "anything", "can_override": false}, "AnB": {"name": "AnB", "group": "Final data", "definition": "random(10..20)", "description": "", 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data", "definition": "if(isornot1=0,\"not {pairs[0]}\",pairs[0])", "description": "", "templateType": "anything", "can_override": false}, "q2a": {"name": "q2a", "group": "Final data", "definition": "if(isornot3=0,\"not {pairs[0]}\",pairs[0])", "description": "", "templateType": "anything", "can_override": false}, "q1b": {"name": "q1b", "group": "Final data", "definition": "if(isornot2=0,\"not {pairs[1]}\",pairs[1])", "description": "", "templateType": "anything", "can_override": false}, "q2b": {"name": "q2b", "group": "Final data", "definition": "if(isornot4=0,\"not {pairs[1]}\",pairs[1])", "description": "", "templateType": "anything", "can_override": false}, "q1": {"name": "q1", "group": "Final data", "definition": "if(isornot1=0,if(isornot2=0,notAnB',notAnB),if(isornot2=0,AnB',AnB))/total", "description": "", "templateType": "anything", "can_override": false}, "q2": {"name": "q2", "group": "Final data", "definition": "if(isornot3=0,if(isornot4=0,notAnB'/(total-A),notAnB/(total-A)),if(isornot4=0,AnB'/A,AnB/A))", "description": "", "templateType": "anything", "can_override": false}, "isornot1": {"name": "isornot1", "group": "Final data", "definition": "random(0,1)", "description": "", "templateType": "anything", "can_override": false}, "isornot2": {"name": "isornot2", "group": "Final data", "definition": "random(1,0)", "description": "", "templateType": "anything", "can_override": false}, "isornot3": {"name": "isornot3", "group": "Ungrouped variables", "definition": "random(0,1)", "description": "", "templateType": "anything", "can_override": false}, "isornot4": {"name": "isornot4", "group": "Ungrouped variables", "definition": "random(0,1)", "description": "", "templateType": "anything", "can_override": false}}, "variablesTest": {"condition": "", "maxRuns": "1000"}, "ungrouped_variables": ["isornot3", "isornot4"], "variable_groups": [{"name": "Final data", "variables": ["nA", "pairs", "nB", "AnB", "AnB'", "notAnB'", "notAnB", "total", "A", "B", "q1a", "q2a", "q1b", "q2b", "q1", "q2", "isornot1", "isornot2"]}], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "gapfill", "useCustomName": false, "customName": "", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>$\\var{total}$ items are sampled. &nbsp;Complete the table.</p>\n<table border=\"1\" cellspacing=\"10\" cellpadding=\"10\">\n<tbody>\n<tr>\n<td></td>\n<td>&nbsp; &nbsp;$\\var{nB}$ &nbsp;&nbsp;</td>\n<td>&nbsp;not $\\var{nB}$&nbsp;</td>\n<td>&nbsp; TOTAL &nbsp;</td>\n</tr>\n<tr>\n<td>&nbsp; &nbsp;$\\var{nA}$ 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