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rebelmaths

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Given a random variable $X$ normally distributed as $\\operatorname{N}(m,\\sigma^2)$ find probabilities $P(X \\gt a),\\; a \\gt m;\\;\\;P(X \\lt b),\\;b \\lt m$.

"}, "tags": ["ACC1012", "checked2015", "MAS1403", "rebelmaths"], "ungrouped_variables": ["units1", "upper", "lower", "p1", "m", "amount", "zupper", "p", "s", "stuff", "tol", "zlower", "prob2", "prob1"], "functions": {}, "variable_groups": [], "showQuestionGroupNames": false, "parts": [{"prompt": "

Find the probability that in a particular week the {amount} is less than {lower} {units1}:

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Probability = ?[[0]](to 2  decimal places)

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Find the probability that in a particular week the {amount} is greater than {upper} {units1}:

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Probability = ?[[1]](to 2  decimal places)

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1. Converting to $\\operatorname{N}(0,1)$

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$\\simplify[all,!collectNumbers]{P(X < {lower}) = P(Z < ({lower} -{m}) / {s}) =1 -P(Z < {m-lower}/{s})} = 1-P(z<\\var{zlower})=1 -\\var{p} = \\var{prob1}$ to 2 decimal places.

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2. Converting to $\\operatorname{N}(0,1)$

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$\\simplify[all,!collectNumbers]{P(X > {upper}) = P(Z > ({upper} -{m}) / {s}) = 1 -P(Z < {upper-m}/{s})} = 1-P(z<\\var{zupper})=1-\\var{p1} = \\var{prob2}$ to 2 decimal places.

", "name": "Julie's copy of Clodagh's copy of Julie's copy of Calculate probabilities from normal distribution, ", "statement": "

The {amount}, $X$, of {stuff}  is normally distributed with mean {m}k Wh and standard deviation {s}{units1}.

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