#ACT 2016 74H Q59 - Standard Deviation

54 messages · Page 1 of 1 (latest)

glass sigil
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hi can someone explain how the answer is supposed to be A (my answer was a C) and how i can identify the answer to questions like this quickly? thanks so much

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muted temple
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like im doing it like this

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it can not be D obviously

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For B and E

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let me draw those

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the red thing is basically the differences between values and mean

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you can see the variation is not that much

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compared to A

glass sigil
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ahhhh that makes a lot of sense,

muted temple
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where the varations would be too much like

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glass sigil
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ok i got that

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how come c is sus though

muted temple
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the mean is 7.5

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and the elements are 2,6,6,10,10,12

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so the variations would be

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umm lets just look at mid ones

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1.5,1.5,2.5,2.5 (ignoring the outliers 2 and 12)

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these values are nothing compared to 4.5

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so yeah it is basically intuition and mental math rn

glass sigil
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ahhh okii thank you so much!! i'll take note of this tysm

muted temple
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Glad to help :)

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Where are you from btw?

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Really jp?

glass sigil
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asia :)) im in japan rn

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yea not japanese tho haha

muted temple
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I seeee.e

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Then?

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Also, are calculators allowed in JP schools?

glass sigil
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ph, and im not studying at a jp school, im finishing up online classes at a school back home and taking the act so i can go to uni here

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i think generally calcs are allowed at the trig level tho regardless of which country ur in?

muted temple
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lmaoo maths

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muted temple
glass sigil
glass sigil
muted temple
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Yeah.

glass sigil
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yeesh that sounds miserable , no wonder you guys are so good at math 😭

muted temple
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Most students first use calculators in uni for like engineering courses.

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You can like do these mentally as long as the datasets are smol

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like 6 values is ig fine

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and the variation is constant

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but I'd be ded if the numbers were like

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2, 5, 25, 76, 1002

glass sigil
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makes sense, i gotcha

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i'll practice more questions like this so i can figure out how to do it mentally

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tysm :>

muted temple
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good luck

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imma go no

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now

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bye