// Numbas version: finer_feedback_settings
{"name": "Modelling 2", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"functions": {}, "rulesets": {}, "variablesTest": {"condition": "", "maxRuns": 100}, "extensions": [], "statement": "<p>Suppose we model the spread of a virus in a certain population as follows. On day one, $\\var{a}$&nbsp;people are infected. On each subsequent day, each infected person gives the cold to $\\var{b}$ others.</p>", "name": "Modelling 2", "variable_groups": [], "tags": [], "ungrouped_variables": ["a", "b", "r"], "advice": "", "variables": {"r": {"definition": "random(5..8)", "description": "", "group": "Ungrouped variables", "templateType": "anything", "name": "r"}, "b": {"definition": "random(2..8)", "description": "", "group": "Ungrouped variables", "templateType": "anything", "name": "b"}, "a": {"definition": "random(1..6)", "description": "", "group": "Ungrouped variables", "templateType": "anything", "name": "a"}}, "parts": [{"variableReplacements": [], "extendBaseMarkingAlgorithm": true, "prompt": "<p>How&nbsp;many people are infected by day 2?&nbsp;[[0]]</p>\n<p>How many people are infected by day 3? [[1]]</p>\n<p>How many people are infected by day 4?&nbsp;[[2]]</p>", "unitTests": [], "showFeedbackIcon": true, "variableReplacementStrategy": "originalfirst", "showCorrectAnswer": true, "gaps": [{"extendBaseMarkingAlgorithm": true, "variableReplacements": [], "failureRate": 1, "checkingAccuracy": "2", "checkVariableNames": false, "unitTests": [], "showFeedbackIcon": true, "variableReplacementStrategy": "originalfirst", "showCorrectAnswer": false, "scripts": {}, "type": "jme", "marks": 1, "customMarkingAlgorithm": "", "checkingType": "dp", "answer": "{a}*{b+1}", "vsetRangePoints": 5, "showPreview": true, "vsetRange": [0, 1], "expectedVariableNames": []}, {"extendBaseMarkingAlgorithm": true, "variableReplacements": [], "failureRate": 1, "checkingAccuracy": "2", "checkVariableNames": false, "unitTests": [], "showFeedbackIcon": true, "variableReplacementStrategy": "originalfirst", "showCorrectAnswer": false, "scripts": {}, "type": "jme", "marks": 1, "customMarkingAlgorithm": "", "checkingType": "dp", "answer": "{a}*{b+1}^2", "vsetRangePoints": 5, "showPreview": true, "vsetRange": [0, 1], "expectedVariableNames": []}, {"extendBaseMarkingAlgorithm": true, "variableReplacements": [], "failureRate": 1, "checkingAccuracy": "2", "checkVariableNames": false, "unitTests": [], "showFeedbackIcon": true, "variableReplacementStrategy": "originalfirst", "showCorrectAnswer": false, "scripts": {}, "type": "jme", "marks": 1, "customMarkingAlgorithm": "", "checkingType": "dp", "answer": "{a}*{b+1}^3", "vsetRangePoints": 5, "showPreview": true, "vsetRange": [0, 1], "expectedVariableNames": []}], "type": "gapfill", "marks": 0, "customMarkingAlgorithm": "", "scripts": {}, "sortAnswers": false}, {"variableReplacements": [], "extendBaseMarkingAlgorithm": true, "prompt": "<p>Given the following recurrence relation for the number of people infected by day n, find A and B:</p>\n<p>\\[C(n)=\\begin{cases}&nbsp; A &amp; if &amp; n=1\\\\&nbsp; &nbsp; C(n-1) + [C(n-1) \\times B] &amp; if &amp; n\\geq2 \\end{cases}\\]</p>\n<p>A =&nbsp;[[0]] and B = [[1]]</p>", "unitTests": [], "showFeedbackIcon": true, "variableReplacementStrategy": "originalfirst", "showCorrectAnswer": true, "gaps": [{"extendBaseMarkingAlgorithm": true, "variableReplacements": [], "failureRate": 1, "checkingAccuracy": 0.001, "checkVariableNames": false, "unitTests": [], "showFeedbackIcon": true, "variableReplacementStrategy": "originalfirst", "showCorrectAnswer": true, "scripts": {}, "type": "jme", "marks": 1, "customMarkingAlgorithm": "", "checkingType": "absdiff", "answer": "{a}", "vsetRangePoints": 5, "showPreview": true, "vsetRange": [0, 1], "expectedVariableNames": []}, {"extendBaseMarkingAlgorithm": true, "variableReplacements": [], "failureRate": 1, "checkingAccuracy": 0.001, "checkVariableNames": false, "unitTests": [], "showFeedbackIcon": true, "variableReplacementStrategy": "originalfirst", "showCorrectAnswer": true, "scripts": {}, "type": "jme", "marks": 1, "customMarkingAlgorithm": "", "checkingType": "absdiff", "answer": "{b}", "vsetRangePoints": 5, "showPreview": true, "vsetRange": [0, 1], "expectedVariableNames": []}], "type": "gapfill", "marks": 0, "customMarkingAlgorithm": "", "scripts": {}, "sortAnswers": false}], "metadata": {"description": "", "licence": "None specified"}, "preamble": {"js": "", "css": ""}, "type": "question", "contributors": [{"name": "Marie Nicholson", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/1799/"}]}]}], "contributors": [{"name": "Marie Nicholson", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/1799/"}]}