normal distribution | Revision Server | Page 1

normal fiber Aug 1, 2023, 11:40 AM

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is this correct?

wary steppe Aug 1, 2023, 4:32 PM

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normal fiber is this correct?

a normal distribution never actually reaches 0, so they shouldn't end at 3 standard deviations above and below the mean

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another point to mention is that there is a point of inflection at one standard deviation away from the mean on either side

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apart from that, it looks pretty good to me

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you can use desmos to check your answers

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@normal fiber here are the points of inflection labelled

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you should be able to see that the bell curve changes from convex to concave and concave to convex at these points

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sorry, just realised this was for stats gcse

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don't think you'll need the extra detail surrounding the points of inflection

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but you should really flatten the curve so it continues going but never reaches 0

normal fiber Aug 1, 2023, 4:51 PM

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wary steppe but you should really flatten the curve so it continues going but never reaches ...

x value never reaches 0 u mean?

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kind of like a reciprocal graph

wary steppe Aug 1, 2023, 4:51 PM

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normal fiber x value never reaches 0 u mean?

the 'y' value

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the height basically

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it should never touch the 'x-axis'

normal fiber Aug 1, 2023, 4:53 PM

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what the heck is points of inflection

wary steppe Aug 1, 2023, 4:53 PM

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it looks like it does on desmos, but in reality it's always above it, and where it looks like it touches the x-axis its actually just slightly above it

wary steppe Aug 1, 2023, 4:53 PM

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normal fiber what the heck is points of inflection

do you know what convex and concave curves are

normal fiber Aug 1, 2023, 4:53 PM

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ik what concave and convex lens are in physics lmao

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not curves tho

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also are u really year 10

wary steppe Aug 1, 2023, 4:54 PM

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normal fiber also are u really year 10

yeah

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idk if this really will help much

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concave up is the same as convex

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basically the curve sort of 'changes direction'

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you don't need to know this for gcse stats i don't think

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you'll learn all about it if you do a level maths

normal fiber Aug 1, 2023, 4:56 PM

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would this be fine then

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the mean +- 3 standard deviations is where y > 0

normal fiber Aug 1, 2023, 4:57 PM

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wary steppe you can use desmos to check your answers

by using the N(μ,σ^2) notation?

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where mu is the mean and lowercase sigma is the variance

wary steppe Aug 1, 2023, 4:58 PM

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normal fiber by using the N(μ,σ^2) notation?

the σ represents standard deviation

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variance is σ^2

normal fiber Aug 1, 2023, 4:58 PM

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squared i mean

wary steppe Aug 1, 2023, 4:59 PM

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yeah

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i think that's fine

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i would still carry on the lines a bit further tho

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sicne the curve doesn't stop 3σ above and below the mean

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something like this

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@normal fiber

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idk if that's just me being picky

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you would probably still get the marks for what you've drawn

normal fiber Aug 1, 2023, 5:01 PM

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i basically did that

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just that mine is more squashed

wary steppe Aug 1, 2023, 5:01 PM

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i just extended yours past 3σ

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just a small detail

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i'm not familiar with the gcse stats course so i'm not sure exactly what you have to draw to get the marks

normal fiber Aug 1, 2023, 5:02 PM

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haven’t found any exam qs to do with normal distribution

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only in control charts

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but not for normal distribution itself

wary steppe Aug 1, 2023, 5:05 PM

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normal fiber i basically did that

never mind, forget what i said

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apparently for gcse stats they want you to only focus on 3σ above and below the mean

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that's fine, what you've got there

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i guess its just important to know for later that the curve continues forever

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gcse stats looks horrific

normal fiber Aug 1, 2023, 5:10 PM

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wary steppe gcse stats looks horrific

it is

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especially the writeups

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sampling

wary steppe Aug 1, 2023, 5:10 PM

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feel bad for you 😭

normal fiber Aug 1, 2023, 5:32 PM

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i like comparing box plots

#normal distribution