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Category: Probability and Statistics

A-bag-contains-6-white-4-red-amp-10-black-balls-If-two-balls-are-drawn-at-random-what-is-the-probability-of-both-being-black-

Question Number 106405 by john santu last updated on 05/Aug/20 $$\mathrm{A}\:\mathrm{bag}\:\mathrm{contains}\:\mathrm{6}\:\mathrm{white},\:\mathrm{4}\:\mathrm{red}\:\&\:\mathrm{10} \\ $$$$\mathrm{black}\:\mathrm{balls}.\:\mathrm{If}\:\mathrm{two}\:\mathrm{balls}\:\mathrm{are}\:\mathrm{drawn} \\ $$$$\mathrm{at}\:\mathrm{random},\:\mathrm{what}\:\mathrm{is}\:\mathrm{the} \\ $$$$\mathrm{probability}\:\mathrm{of}\:\mathrm{both}\:\mathrm{being}\:\mathrm{black}\:? \\ $$ Answered by bemath last updated on…

A-box-contains-12-balls-numbered-from-1-to-12-4-balls-are-selected-successively-without-replacement-Given-X-the-variable-the-number-of-even-numbered-balls-selected-Determine-the-probability-typ

Question Number 105934 by Ar Brandon last updated on 01/Aug/20 $$\mathrm{A}\:\mathrm{box}\:\mathrm{contains}\:\mathrm{12}\:\mathrm{balls}\:\mathrm{numbered}\:\mathrm{from}\:\mathrm{1}\:\mathrm{to}\:\mathrm{12}.\:\mathrm{4}\:\mathrm{balls} \\ $$$$\mathrm{are}\:\mathrm{selected}\:\mathrm{successively}\:\mathrm{without}\:\mathrm{replacement}.\:\mathrm{Given} \\ $$$$“\mathrm{X}''\:\mathrm{the}\:\mathrm{variable}\:“\mathrm{the}\:\mathrm{number}\:\mathrm{of}\:\mathrm{even}\:\mathrm{numbered}\:\mathrm{balls} \\ $$$$\mathrm{selected}''.\:\mathrm{Determine}\:\mathrm{the}\:\mathrm{probability}\:\mathrm{type}/\mathrm{law}\:\mathrm{of}\:\mathrm{X}. \\ $$ Answered by bobhans last updated on…

In-a-by-election-20-of-the-electorate-voted-for-Mr-X-If-5-voters-are-chosen-at-random-from-this-electorate-what-is-the-probability-that-20-of-the-sample-voted-for-Mr-X-a-1-b-1-5-c-

Question Number 105812 by Ar Brandon last updated on 31/Jul/20 $$\mathrm{In}\:\mathrm{a}\:\mathrm{by}-\mathrm{election}\:\mathrm{20\%}\:\mathrm{of}\:\mathrm{the}\:\mathrm{electorate}\:\mathrm{voted}\:\mathrm{for}\:\mathrm{Mr}\:\mathrm{X}. \\ $$$$\mathrm{If}\:\mathrm{5}\:\mathrm{voters}\:\mathrm{are}\:\mathrm{chosen}\:\mathrm{at}\:\mathrm{random}\:\mathrm{from}\:\mathrm{this}\:\mathrm{electorate},\:\mathrm{what} \\ $$$$\mathrm{is}\:\mathrm{the}\:\mathrm{probability}\:\mathrm{that}\:\mathrm{20\%}\:\mathrm{of}\:\mathrm{the}\:\mathrm{sample}\:\mathrm{voted}\:\mathrm{for}\:\mathrm{Mr}\:\mathrm{X}\:? \\ $$$$\left(\mathrm{a}\right)\:\mathrm{1}\:\:\:\:\left(\mathrm{b}\right)\:\frac{\mathrm{1}}{\mathrm{5}}\:\:\:\:\left(\mathrm{c}\right)\:\frac{\mathrm{1}}{\mathrm{625}}\:\:\:\:\left(\mathrm{d}\right)\:\frac{\mathrm{256}}{\mathrm{625}} \\ $$ Answered by Don08q last updated on…

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Question Number 105670 by Ar Brandon last updated on 30/Jul/20 $$\mathrm{A}\:\mathrm{machine}\:\mathrm{manufactures}\:\mathrm{washers},\:\mathrm{and}\:\mathrm{20\%}\:\mathrm{of}\:\mathrm{the}\:\mathrm{production}\:\mathrm{is} \\ $$$$\mathrm{substandard}.\:\mathrm{A}\:\mathrm{random}\:\mathrm{sample}\:\mathrm{o}\:\mathrm{f}\:\mathrm{10}\:\mathrm{washers}\:\mathrm{is}\:\mathrm{selected}. \\ $$$$\mathrm{Find}\:\mathrm{the}\:\mathrm{mean}\:\mathrm{and}\:\mathrm{standard}\:\mathrm{deviation}\:\mathrm{of}\:\mathrm{the}\:\mathrm{number} \\ $$$$\mathrm{of}\:\mathrm{substandard}\:\mathrm{washers}\:\mathrm{in}\:\mathrm{the}\:\mathrm{sample}. \\ $$ Answered by Ar Brandon last updated…

A-box-contains-5-white-balls-3-black-balls-and-2-red-balls-of-the-same-size-A-ball-is-selected-at-random-from-the-box-and-then-replaced-A-second-ball-is-then-selected-Find-the-probability-of-ob

Question Number 104761 by byaw last updated on 23/Jul/20 $$ \\ $$$$\:\:\mathrm{A}\:\mathrm{box}\:\mathrm{contains}\:\mathrm{5}\:\mathrm{white}\:\mathrm{balls},\:\mathrm{3}\:\mathrm{black} \\ $$$$\mathrm{balls}\:\mathrm{and}\:\mathrm{2}\:\mathrm{red}\:\mathrm{balls}\:\mathrm{of}\:\mathrm{the}\:\mathrm{same} \\ $$$$\mathrm{size}.\:\mathrm{A}\:\mathrm{ball}\:\mathrm{is}\:\mathrm{selected}\:\mathrm{at}\:\mathrm{random} \\ $$$$\mathrm{from}\:\mathrm{the}\:\mathrm{box}\:\mathrm{and}\:\mathrm{then}\:\mathrm{replaced}.\:\mathrm{A} \\ $$$$\mathrm{second}\:\mathrm{ball}\:\mathrm{is}\:\mathrm{then}\:\mathrm{selected}.\:\mathrm{Find} \\ $$$$\mathrm{the}\:\mathrm{probability}\:\mathrm{of}\:\mathrm{obtaining}\: \\ $$$$\:\mathrm{one}\:\mathrm{black}\:\mathrm{ball}\:\mathrm{or}\:\mathrm{red}\:\mathrm{ball}\:\mathrm{in}\:\mathrm{any} \\…

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Question Number 104708 by byaw last updated on 23/Jul/20 $$ \\ $$$$\:\mathrm{A}\:\mathrm{bag}\:\mathrm{contains}\:\mathrm{12}\:\mathrm{white}\:\mathrm{balls}\: \\ $$$$\mathrm{and}\:\mathrm{8}\:\mathrm{black}\:\mathrm{balls},\:\mathrm{another}\: \\ $$$$\mathrm{contains}\:\mathrm{10}\:\mathrm{white}\:\mathrm{balls}\:\mathrm{and}\:\mathrm{15} \\ $$$$\mathrm{black}\:\mathrm{balls}.\:\mathrm{If}\:\mathrm{two}\:\mathrm{balls}\:\mathrm{are}\:\mathrm{drawn} \\ $$$$\mathrm{wthout}\:\mathrm{replacement}\:\mathrm{from}\:\mathrm{each} \\ $$$$\mathrm{bag},\:\mathrm{find}\:\mathrm{the}\:\mathrm{probability}\:\mathrm{that}:\: \\ $$$$ \\…