// Numbas version: finer_feedback_settings
{"name": "Exponential population growth from graph", "extensions": ["geogebra"], "custom_part_types": [{"source": {"pk": 1, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/1/edit"}, "name": "Yes/no", "short_name": "yes-no", "description": "<p>The student is shown two radio choices: \"Yes\" and \"No\". One of them is correct.</p>", "help_url": "", "input_widget": "radios", "input_options": {"correctAnswer": "if(eval(settings[\"correct_answer_expr\"]), 0, 1)", "hint": {"static": true, "value": ""}, "choices": {"static": true, "value": ["Yes", "No"]}}, "can_be_gap": true, "can_be_step": true, "marking_script": "mark:\nif(studentanswer=correct_answer,\n  correct(),\n  incorrect()\n)\n\ninterpreted_answer:\nstudentAnswer=0\n\ncorrect_answer:\nif(eval(settings[\"correct_answer_expr\"]),0,1)", "marking_notes": [{"name": "mark", "description": "This is the main marking note. It should award credit and provide feedback based on the student's answer.", "definition": "if(studentanswer=correct_answer,\n  correct(),\n  incorrect()\n)"}, {"name": "interpreted_answer", "description": "A value representing the student's answer to this part.", "definition": "studentAnswer=0"}, {"name": "correct_answer", "description": "", "definition": "if(eval(settings[\"correct_answer_expr\"]),0,1)"}], "settings": [{"name": "correct_answer_expr", "label": "Is the answer \"Yes\"?", "help_url": "", "hint": "An expression which evaluates to <code>true</code> or <code>false</code>.", "input_type": "mathematical_expression", "default_value": "true", "subvars": false}], "public_availability": "always", "published": true, "extensions": []}], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"name": "Exponential population growth from graph", "tags": [], "metadata": {"description": "<p>The student is shown an exponential graph and asked to evaluate the function at some given value.</p>\n<p>They are also asked whether or not the model is valid for all real inputs, but they only give a yes/no response. The reasoning is explained in the advice but is not required from students.</p>", "licence": "Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International"}, "statement": "<p>The following graph shows the growth of a population, $P$ of {object} as a function of time, $t$, given in {timeperiod}.</p>", "advice": "<p>The value of $P$ when $t=\\var{time}$ can be read off the graph.</p>\n<p>We go along the horizontal axis until we find $\\var{time}$.</p>\n<p>Then we go vertically up until we meet the graph.</p>\n<p>Then we go left until we reach the vertical axis, and we read off the value there, which is approximately $\\var{answer1}$.</p>\n<p>This graph is not valid as a model for all values of $t$.</p>\n<p>Firstly, it does not normally make sense to talk about negative values of time, so the graph is only valid for $t \\geq 0$.</p>\n<p>Secondly, according to this graph, the population would keep increasing exponentially forever. This cannot be the case. At some point the population will slow down and/or stop its growth rate, and this model will no longer apply.</p>", "rulesets": {}, "extensions": ["geogebra"], "builtin_constants": {"e": true, "pi,\u03c0": true, "i": true}, "constants": [], "variables": {"objectlist": {"name": "objectlist", "group": "Ungrouped variables", "definition": "['bacteria','amoebas','virus particles','mould','cockroaches','aphids']", "description": "", "templateType": "anything", "can_override": false}, "objectchoice": {"name": "objectchoice", "group": "Ungrouped variables", "definition": "random(0..5)", "description": "", "templateType": "anything", "can_override": false}, "object": {"name": "object", "group": "Ungrouped variables", "definition": "objectlist[objectchoice]", "description": "", "templateType": "anything", "can_override": false}, "k": {"name": "k", "group": "Ungrouped variables", "definition": "random(1..3)", "description": "", "templateType": "anything", "can_override": false}, "a": {"name": "a", "group": "Ungrouped variables", "definition": "random(2..4)", "description": "", "templateType": "anything", "can_override": false}, "defs": {"name": "defs", "group": "Ungrouped variables", "definition": "[\n  ['k',k],['a',a],['b',1],['c',0],['xm',time + 1],['ym',ans + ceil(ans/10)]\n  ]", "description": "", "templateType": "anything", "can_override": false}, "ans": {"name": "ans", "group": "Ungrouped variables", "definition": "k * a^time", "description": "", "templateType": "anything", "can_override": false}, "time": {"name": "time", "group": "Ungrouped variables", "definition": "random(1..5)", "description": "", "templateType": "anything", "can_override": false}, "timeperiodlist": {"name": "timeperiodlist", "group": "Ungrouped variables", "definition": "['hours','days','weeks','months','years']", "description": "", "templateType": "anything", "can_override": false}, "answer1": {"name": "answer1", "group": "Ungrouped variables", "definition": "k*a^time", "description": "", "templateType": "anything", "can_override": false}, "answer2": {"name": "answer2", "group": "Ungrouped variables", "definition": "k*(a^time)/2", "description": "", "templateType": "anything", "can_override": false}, "answer3": {"name": "answer3", "group": "Ungrouped variables", "definition": "k*(a^time)*2", "description": "", "templateType": "anything", "can_override": false}, "answer4": {"name": "answer4", "group": "Ungrouped variables", "definition": "time", "description": "", "templateType": "anything", "can_override": false}, "timeperiodchoice": {"name": "timeperiodchoice", "group": "Ungrouped variables", "definition": "random(0..4)", "description": "", "templateType": "anything", "can_override": false}, "timeperiod": {"name": "timeperiod", "group": "Ungrouped variables", "definition": "timeperiodlist[timeperiodchoice]", "description": "", "templateType": "anything", "can_override": false}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["objectlist", "objectchoice", "object", "k", "a", "defs", "ans", "time", "timeperiodlist", "answer1", "answer2", "answer3", "answer4", "timeperiodchoice", "timeperiod"], "variable_groups": [], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "information", "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>{geogebra_applet('https://www.geogebra.org/m/fyfns8hu',defs)}</p>"}, {"type": "1_n_2", "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>What is the value of the population $P$ after $\\var{time}$ {timeperiod}?&nbsp;</p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": true, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["{answer1}", "{answer2}", "{answer3}", "{answer4}"], "matrix": ["1", 0, 0, 0], "distractors": ["", "", "", ""]}, {"type": "yes-no", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>Is this model valid for all values of $t$? Why or why not?</p>", "settings": {"correct_answer_expr": "false"}}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always", "type": "question", "contributors": [{"name": "Merryn Horrocks", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/4052/"}], "resources": []}]}], "contributors": [{"name": "Merryn Horrocks", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/4052/"}]}