AS Edexcel S1 - (5th June 2015) Exam Thread

Original post by .catherine.

will percentiles come up? because im not really sure how to do them..

also when the question asks which average is more suitable how do you answer that?

Its in the specification so as with everything else which features in the spec, there is a chance it will come up. Same method as using interpolation to find quartiles but you're trying the find the (p/100)(n)th piece of data where p is the Pth percentile. So if they ask for the 60th percentile - multiple p/100 by the sum of frequencies and interpolate as you do for quartiles.

Use quartiles/IQR for skewed data as mean and S.d is effected by skew and extreme values.

Reply 383

Bilalnaseerr

2

Original post by Bustamove

When drawing a box plot with outliers, do you end the "whiskers" at the outlier limits or do you end it at the next value which is not outside the outlier?

are both of these acceptable?

When I say "whiskers", I don't know the exact word for it but it's the points where the highest value and the lowest value is pointed out when there is no outliers
(Hope this makes sense)

help?

For this I've been taught to do the outlier boundary if there's an outlier on that side of the box and whisker otherwise just use your highest/lowest values

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Reply 384

winstar

2

For rounding numbers...how many sf/dp should we round?
Also is there a fixed way to round the value of money?like a whole number?

Reply 385

iman.k

1

I find Probability so hard and I've done all the Past paper Qs relating to them anyone know what else can be done Cuz I get stuck on them so so much

Reply 386

Original post by iman.k

I find Probability so hard and I've done all the Past paper Qs relating to them anyone know what else can be done Cuz I get stuck on them so so much

what exactly are you stuck on, if you've done all the past papers you should be ready to go?

Reply 387

кяя

11

Hey, can someone tell me why you'd use Swl/Sll and not Swl//Sww in this question?

Thank you!!

Also, does anyone know where I can get a good histogram explanation? I SUCK at histograms (esp. telling the width and height of a bar).

Reply 388

Original post by Hai_Ann

Does anyone have a list of coding questions that have come up in past exam papers?
I haven't touched upon coding yet... :redface:

that isn't part of Edexcel stats

Reply 389

OP

Original post by Hai_Ann

Does anyone have a list of coding questions that have come up in past exam papers?
I haven't touched upon coding yet... :redface:

Original post by Virolite

that isn't part of Edexcel stats

I think coding is in edexcel S1... there was a coding question in june 2014 paper, question 2... nothing really major though... There's also one on jan 2011 question 4.... and I'm sure there's a few more here and there in the edexcel papers..

Reply 390

thenextchemist

21

Original post by Hai_Ann

Does anyone have a list of coding questions that have come up in past exam papers?
I haven't touched upon coding yet... :redface:

There's coding in the June 2014 (R) paper

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Reply 391

Original post by кяя

Also, does anyone know where I can get a good histogram explanation? I SUCK at histograms (esp. telling the width and height of a bar).

You want to compare class width to the width of a bar to find the width of another classes' bar, then use "f = FD x CW" to work out the height as FD is common to the height of both bars (if that makes any sense)

Reply 392

OP

Original post by кяя

Hey, can someone tell me why you'd use Swl/Sll and not Swl//Sww in this question?.

Original post by Virolite

you would need to use Swl and Sww to find b in the equation of the regression line

For that question, you use Swl/Sll to find b instead of Swl/Sww because the regression line is w=a+bl
if you look at bl, it has to be Sll instead of Sww because l is the function and b is just the coefficient.... if it was bw, then you use Sww instead of Sll

think of it like this:
Equation for regression line y=a+bx

so therefore, to find b, it's b=Sxy/Sxx
Sxx is used instead of Syy because x is the function and b is just the coefficient in the regression line

I hope this makes sense :smile:

(edited 8 years ago)

Reply 393

Original post by Bustamove

I think coding is in edexcel S1... there was a coding question in june 2014 paper, question 2... nothing really major though... There's also one on jan 2011 question 4.... and I'm sure there's a few more here and there in the edexcel papers..

Maybe in the international papers but it's not in the standard stats spec

Reply 394

Original post by Bustamove

I think coding is in edexcel S1... there was a coding question in june 2014 paper, question 2... nothing really major though... There's also one on jan 2011 question 4.... and I'm sure there's a few more here and there in the edexcel papers..

that's just using the expected mean, not necessarily coding as such

Reply 395

кяя

11

Original post by Bustamove

For that question, you use Swl/Sll to find b instead of Swl/Sww because the regression line is w=a+bl
if you look at bl, it has to be Sll instead of Sww because l is the function and b is just the coefficient.... if it was bw, then you use Sww instead of Sll

think of it like this:
Equation for regression line y=a+bx

so therefore, to find b, it's b=Sxy/Sxx
Sxx is used instead of Syy because x is the function and b is just the coefficient in the regression line

I hope this makes sense :smile:

Ahh, that makes sense now. Thanks!

So if the equation was, for example, x=a+by it would be Sxy/Syy?

Reply 396

OP

Original post by Virolite

that's just using the expected mean, not necessarily coding as such

yea, I haven't found anything which is massive in terms of coding, only small minor questions such as those, but it's still there... gonna learn it just in case :wink:

(edited 8 years ago)

Reply 397

ludmila

3

Original post by Virolite

Maybe in the international papers but it's not in the standard stats spec

There IS coding in the Edexcel specification. It is under Measures of location — mean, median, mode: "Data may be discrete, continuous,grouped or ungrouped.Understanding and use of coding."

Reply 398

OP