// Numbas version: exam_results_page_options
{"name": "Standard deviation of a list of numbers with hints", "extensions": ["stats"], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"extensions": ["stats"], "variables": {"var": {"name": "var", "description": "", "definition": "sigma^2", "group": "Ungrouped variables", "templateType": "anything"}, "x": {"name": "x", "description": "", "definition": "random(4,5,8)", "group": "Ungrouped variables", "templateType": "anything"}, "sigma": {"name": "sigma", "description": "", "definition": "stdev(data)", "group": "Ungrouped variables", "templateType": "anything"}, "data": {"name": "data", "description": "", "definition": "repeat(random(1..30),x)", "group": "Ungrouped variables", "templateType": "anything"}, "mean": {"name": "mean", "description": "", "definition": "mean(data)", "group": "Ungrouped variables", "templateType": "anything"}}, "showQuestionGroupNames": false, "advice": "<p>Standard deviation = $\\sqrt{\\frac{\\Sigma (x-\\text{mean})^2}{n}}$</p>\n<p>What is the mean? Add up the numbers and divide by the number of numbers getting an answer of {mean}.</p>\n<p>Now, subtract the mean individually from each of the numbers given and square the result.&nbsp;</p>\n<p>Now add up these results. This is the '$\\Sigma (x-\\text{mean})^2$' part in the formula.<br/>Divide by {x}&nbsp;the number of values. This gives an answer of {var}.</p>\n<p>Finally, find the square root to get an answer of {sigma}.</p>", "tags": ["rebel", "Rebel", "REBEL", "rebelmaths"], "name": "Standard deviation of a list of numbers with hints", "variablesTest": {"maxRuns": 100, "condition": ""}, "metadata": {"description": "<p>Just showing how to use the stdev function from the stats extension&nbsp;to calculate the standard deviation of a list of numbers.</p>\n<p>rebelmaths</p>", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "<p>Find the Standard Deviation</p>", "type": "question", "rulesets": {}, "functions": {}, "variable_groups": [], "ungrouped_variables": ["data", "sigma", "x", "mean", "var"], "preamble": {"js": "", "css": ""}, "parts": [{"steps": [{"type": "information", "showCorrectAnswer": true, "marks": 0, "variableReplacementStrategy": "originalfirst", "scripts": {}, "variableReplacements": [], "prompt": "<p>Standard deviation = $\\sqrt{\\frac{\\Sigma (x-\\text{mean})^2}{n}}$</p>\n<p>To find the standard deviation, first find the mean of the list of numbers.&nbsp;</p>\n<p>What is the mean?</p>\n<p>Now, subtract the mean individually from each of the numbers given and square the result.&nbsp;</p>\n<p>Now add up these results. This is the '$\\Sigma (x-\\text{mean})^2$' part in the formula.<br/>Divide by $n$ where $n$ is the number of values.</p>\n<p>Finally, find the square root.</p>"}], "showCorrectAnswer": true, "precision": "1", "showPrecisionHint": false, "minValue": "{sigma}", "precisionType": "dp", "prompt": "<p>Find the standard deviation of the following list&nbsp;of numbers {data}.</p>\n<p>Give your answer correct to one decimal place.</p>", "precisionMessage": "<p>You have not given your answer to the correct number of decimal places.</p>", "stepsPenalty": "1", "type": "numberentry", "precisionPartialCredit": 0, "marks": "5", "correctAnswerFraction": false, "variableReplacementStrategy": "originalfirst", "scripts": {}, "strictPrecision": false, "maxValue": "{sigma}", "allowFractions": false, "variableReplacements": []}], "question_groups": [{"name": "", "pickingStrategy": "all-ordered", "questions": [], "pickQuestions": 0}], "contributors": [{"name": "Julie Crowley", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/113/"}]}]}], "contributors": [{"name": "Julie Crowley", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/113/"}]}