// Numbas version: exam_results_page_options {"name": "PDF and CDF of continuous uniform random variable, ", "extensions": ["stats"], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"variable_groups": [], "variables": {"a": {"templateType": "anything", "group": "Ungrouped variables", "definition": "random(-5..5)", "name": "a", "description": ""}, "x1": {"templateType": "anything", "group": "Ungrouped variables", "definition": "a+random(1..4)", "name": "x1", "description": ""}, "b": {"templateType": "anything", "group": "Ungrouped variables", "definition": "a+random(5..12)", "name": "b", "description": ""}}, "ungrouped_variables": ["a", "x1", "b"], "rulesets": {"std": ["all", "fractionNumbers", "!collectNumbers", "!noLeadingMinus"]}, "name": "PDF and CDF of continuous uniform random variable, ", "functions": {}, "showQuestionGroupNames": false, "parts": [{"scripts": {}, "gaps": [{"answer": "1/{b-a}", "showCorrectAnswer": true, "vsetrange": [0, 1], "scripts": {}, "checkvariablenames": false, "expectedvariablenames": [], "notallowed": {"message": "

input as a fraction and not a decimal

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Input as a fraction or an integer.

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\n

What is the PDF of $X$? Input all answers as fractions or integers, not as decimals.

\n \n \n \n \n \n \n \n \n \n \n \n \n
$f_X(x) = \\left \\{ \\begin{array}{l} \\phantom{{.}} \\\\\\phantom{{.}} \\\\ \\phantom{{.}} \\\\ \\phantom{{.}}\\end{array} \\right .$[[0]]$\\var{a} \\leq x \\leq \\var{b},$
[[1]]otherwise
\n

 

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input numbers as fractions or integers and not as decimals

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input numbers as fractions or integers and not as decimals

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Compute the CDF $F_X(x)$ of $X$.

\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n
$F_X(x) = \\left \\{ \\begin{array}{l} \\phantom{{.}} \\\\ \\phantom{{.}} \\\\ \\phantom{{.}} \\\\ \\phantom{{.}} \\\\ \\phantom{{.}}\\\\ \\phantom{{.}}\\\\ \\phantom{{.}} \\end{array} \\right .$[[0]]$x \\lt \\var{a},$
  
[[1]]$\\var{a} \\leq x \\leq \\var{b}$
  
[[2]]$ x \\gt \\var{b},$
  
\n

Input all numbers as fractions or integers in the above formulae.

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Input all numbers as fractions or integers.

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Also, using the distribution function above find:

\n

$P( X \\ge \\var{x1})=\\;\\;$[[0]]

\n

(input your answer as a fraction or integer and not as a decimal).

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Suppose $X$ is a continuous uniform random variable defined on $[\\var{a},\\;\\var{b}]$.

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05/02/2013:

\n

First draft finished. 

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$X$ is a continuous uniform random variable defined on $[a,\\;b]$. Find the PDF and CDF of $X$ and find  $P(X \\ge c)$.

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a)

\n

The PDF is given by:

\n

 

\n \n \n \n \n \n \n \n \n \n \n \n \n
$f_X(x) = \\left \\{ \\begin{array}{l} \\phantom{{.}} \\\\\\phantom{{.}} \\\\ \\phantom{{.}} \\\\ \\phantom{{.}}\\end{array} \\right .$\\[\\frac{1}{\\var{b}-(\\var{a})}=\\frac{1}{\\var{b-a}}\\]$\\var{a} \\leq x \\leq \\var{b},$
$0$otherwise
\n

b) The CDF is given by:

\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n
$F_X(x) = \\left \\{ \\begin{array}{l} \\phantom{{.}} \\\\ \\phantom{{.}} \\\\ \\phantom{{.}} \\\\ \\phantom{{.}} \\\\ \\phantom{{.}}\\\\ \\phantom{{.}}\\\\ \\phantom{{.}} \\end{array} \\right .$$0$$x \\lt \\var{a},$
  
\\[\\simplify{(x-{a})/{b-a}}\\]$\\var{a} \\leq x \\leq \\var{b}$
  
1$ x \\gt \\var{b},$
  
\n

c)

\n

\\[P(X \\ge \\var{x1})=1-F_X(\\var{x1})=1-\\simplify[std]{({x1}-{a})/{b-a}={b-x1}/{b-a}}\\]

\n

 

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