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# S1 Help-A lvl! 4 Questions Watch

1. ..
2. any1? :P
3. :O .
4. Q1 I think the answer is 1. They are not independent as P(boys) * P(liked game) isn't P(BnG) - boys intersection game, as some girls also liked the game.

Q2, use the formula z = (x - mean) / st. dev. Pretty straight forward, turn 0.75 into its z value first tho, then work out x from that.

Q3, not too sure why its asking what % like either wine or bottle But independent means P(A) * P(B) = P(AnB) so 0.2*0.3 = 0.06

Q4, well normal distribution means Q1 to the mean is the same as the mean to Q3. So work out Q3 using exactly the same method as Q2, then double the distance from the mean to this Q3 value.

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Updated: December 5, 2010
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