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

If T was 29
that's mod of ( 25-29) which will be 4
do ygm?

You have to solve the inequality basically, do you know how to?

oh okay I understand the mod part, don't think I know how to answer the question though

Reply 781

frozo123

12

Original post by yesyesyesno

oh okay I understand the mod part, don't think I know how to answer the question though

Yeah don't worry, it's more like a hybrid of a C3 and a S1 question aha

Reply 782

Maham88

2

Original post by coolgamer

Do u get it can u explain

basically round 1 has to be lower than round 2 so when the point is 0 in round one the point in round to can be 5,10 or 15. then when the point for round 1 is 5 the point for round 2 has to be 10 or 5 and so on

Original post by kandykissesxox

I don't understand why it can't be 0.2 x 0.2 ?

If it were on a tree diagram then you would have P( 232 <W< 234.622) = 0.20 so you need to connect it to the branch that has a probability of not lying between these values. which is 0.2. this would mean only one jar lies between 232 and 234.622.
the second branch is not lying between 232 and 234.622, so its probability is 0.8 so you have to multiply this by the connecting branch which is jar 2 lying between 232 and 234.622 and that would be 0.8 x 0.2, so adding these up it would be (0.2 x 0.8) + (0.2 x 0.8).

It can't be 0.2 x 0.2 as this would be the probability that neither jars satisfy the inequality.

Reply 784

kandykissesxox

21

Original post by NotNotBatman

If it were on a tree diagram then you would have P( 232 <W< 234.622) = 0.20 so you need to connect it to the branch that has a probability of not lying between these values. which is 0.2. this would mean only one jar lies between 232 and 234.622.
the second branch is not lying between 232 and 234.622, so its probability is 0.8 so you have to multiply this by the connecting branch which is jar 2 lying between 232 and 234.622 and that would be 0.8 x 0.2, so adding these up it would be (0.2 x 0.8) + (0.2 x 0.8).

It can't be 0.2 x 0.2 as this would be the probability that neither jars satisfy the inequality.

I understand, thank you!

Reply 785

Uchiha_

2

Hey could some one please give me a list of things my calculator can do to help me in the exam. I am self studying and I'm not sure of any tricks my calculator can do. I also have a graphical calculator, what can I do with this to help me?

Reply 786

coolgamer

11

Original post by Maham88

basically round 1 has to be lower than round 2 so when the point is 0 in round one the point in round to can be 5,10 or 15. then when the point for round 1 is 5 the point for round 2 has to be 10 or 5 and so on

oh I get it thanks so each time we multiply probability of round 1 and round 2

Reply 787

FluffyCherry

18

when Am I suppose to use the percentage points table?? Like how do I know if the question is asking me to use the percentage points values? like for instance "Find the value of the constant a such that P(Z > a) = 0.01"

Reply 788

Maham88

2

Original post by coolgamer

oh I get it thanks so each time we multiply probability of round 1 and round 2

yeah

Reply 789

NotNotBatman

20

Original post by FluffyCherry

when Am I suppose to use the percentage points table?? Like how do I know if the question is asking me to use the percentage points values? like for instance "Find the value of the constant a such that P(Z > a) = 0.01"

If you cannot solve the Z value but know the area. If the area used in one that is in the percentage points table then use it as you may lose marks for using the normal dist. function table.

For your example look at the table and you should be able to see that your z value is 2.3263.

Reply 790

Craig1998

12

Tip with normal distribution as I used to struggle with it.

A way to help you understand the problem is by drawing the normal curves, for X and for Z. They are visually identical and the X one is the given value where the mean is at the centre, the Z is the standardised value, where 0 is at the centre (so when you do (X - mean)/standard deviation). If your X value is to the left of the mean and the probability is less than, you will need to do 1 - ANS from table. If your value of X is to the right of the mean and the probability is more than, you also need to do 1- ANS. Otherwise it's fine.

These graphs help much more when doing reverse normal questions, as they can help determine whether your Z value is positive or negative (left of 0 on Z graph is negative, right is positive).

Just drawing the X curve can help a lot, and you can always check a reverse normal question by substituting in your value(s).

Reply 791

u_s_e_r

10

What score did everyone get on the IAL Jan 2015 paper?
I did so badly, not looking forward to tomorrow at all. :frown:

Reply 792

GAnil

how many significant figures should I use for S1 edexcel

Reply 793

BP_Tranquility

5

I swear the IAL papers are pretty difficult - is there chance we might be given papers like that tomorrow?

Posted from TSR Mobile

Reply 794

Gilo98

14

Original post by u_s_e_r

What score did everyone get on the IAL Jan 2015 paper?
I did so badly, not looking forward to tomorrow at all. :frown:

Just about to do it, I'll let you know how I get on

Reply 795

mrt1997

I'm really confused on coding... please could someone explain how it relates to each topic and how it can affect each one e.g mean, correlation etc. Thank you :smile:

Reply 796

icexcity_

3

ImageUploadedByStudent Room1433426118.833500.jpg

Can anyone help me with this question? I'm stuck on it for like 20 minutes :frown:

Posted from TSR Mobile

Reply 797

Chewysambe

3

I don't know if I'm being a complete idiot... but i can't draw it... as in for the bar where it's just 8 and for the 11 one??? Won't there be a gap? :frown:

Original post by Chewysambe

I don't know if I'm being a complete idiot... but i can't draw it... as in for the bar where it's just 8 and for the 11 one??? Won't there be a gap? :frown:

Because it's 'to the nearest minute', I imagine the bars will go up to the upper class width.

Original post by icexcity_

x

Which part?

Original post by mrt1997

I'm really confused on coding... please could someone explain how it relates to each topic and how it can affect each one e.g mean, correlation etc. Thank you :smile:

I'm not 100% sure about how it affects correlation. It affects the mean, so if you find the mean of the coded data, you do it by 'undoing' the code, so find the value you put into the code that gets you the coded mean and that's your mean. Variance is not affected by coding.