x Turn on thread page Beta
 You are Here: Home >< A-levels

# Maths statistics help urgent !!!! watch

1. Lengths of slow worms (mm) Frequency
125-139 / 4
140-154 / 4
155-169 / 2
170-184 / 7
185-199 / 20
200-214 / 24
215-229 / 10
2. are they asking for the mean or S.D maybe ?
3. (Original post by the bear)
are they asking for the mean or S.D maybe ?
Find the interquartile range.
sorry for not including that
4. maybe draw a cumulative frequency curve and get it from there ?
5. (Original post by Elehin)
Find the interquartile range.
sorry for not including that
You need to find the difference between the 25th percentile and the 75th percentile.
6. (Original post by the bear)
maybe draw a cumulative frequency curve and get it from there ?
It's something to do with Interpolation.
You first calculate the lower frequency and finding the Value of Q1, then the same for Q3.
I'm not sure where i went wrong as the answer i got is too big.
7. (Original post by Elehin)
Lengths of slow worms (mm) Frequency
125-139 / 4
140-154 / 4
155-169 / 2
170-184 / 7
185-199 / 20
200-214 / 24
215-229 / 10
Find the value for n/4, 3n/4, use interpolation for both and substract the answers for the upperquartile (3n/4) by the lower quartile (n/4)
8. (Original post by Elehin)
It's something to do with Interpolation.
You first calculate the lower frequency and finding the Value of Q1, then the same for Q3.
I'm not sure where i went wrong as the answer i got is too big.
Post your working and we can check it.
9. (Original post by kkboyk)
Find the value for n/4, 3n/4, use interpolation for both and substract the answers for the upperquartile (3n/4) by the lower quartile (n/4)
I did exactly those steps but got the wrong answer.
Here's my steps

LQ is 71/4 = 17.75 ,round this to 18
Find where 18 lies on the table.

M - 184.5 / 199.5-184.5 = 18 - 7/ 20 - 7

This gives 446.5

UQ IS 71*3/4 = 53.25

m - 199.5 / 214.5 -199.5 = 53.25 - 20 / 24 - 20
This gives 124.6

UQ - LQ gives a negative number ?
where did i go wrong ?
10. (Original post by Elehin)
I did exactly those steps but got the wrong answer.
Here's my steps

LQ is 71/4 = 17.75 ,round this to 18
Find where 18 lies on the table.

M - 184.5 / 199.5-184.5 = 18 - 7/ 20 - 7

This gives 446.5

UQ IS 71*3/4 = 53.25

m - 199.5 / 214.5 -199.5 = 53.25 - 20 / 24 - 20
This gives 124.6

UQ - LQ gives a negative number ?
where did i go wrong ?
Can you upload a picture of your working since I can't understand much here, sorry

The problem is in your linear interpolation:

I'd use Lower boundary x class width x (how far into the group the mean lies)/frequency
11. (Original post by kkboyk)
Can you upload a picture of your working since I can't understand much here, sorry

The problem is in your linear interpolation:

I'd use Lower boundary x class width x (how far into the group the mean lies)/frequency
Won't be able to provide a picture at this moment.
The method which i have used is correct from looking at examples from the Edexcel book , however i don't seem to know where i went wrong.

Can you just do the question for me? I already know what the answer is but i don't seem to know the process of getting it.
12. (Original post by Elehin)
Won't be able to provide a picture at this moment.
The method which i have used is correct from looking at examples from the Edexcel book , however i don't seem to know where i went wrong.

Can you just do the question for me? I already know what the answer is but i don't seem to know the process of getting it.
Just found this.

It's against the forum rule to post full solutions as people will take advantage of this, and would not develop themselves in Mathematics.

Turn on thread page Beta
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: October 19, 2015
Today on TSR

### Loughborough better than Cambridge

Loughborough at number one

### Can I date a girl with no boobs?

Poll
Help with your A-levels

## All the essentials

### Student life: what to expect

What it's really like going to uni

### Essay expert

Learn to write like a pro with our ultimate essay guide.

### Uni match

Our tool will help you find the perfect course for you

### Create a study plan

Get your head around what you need to do and when with the study planner tool.

### Resources by subject

Everything from mind maps to class notes.

### Degrees without fees

Discover more about degree-level apprenticeships.

### Study tips from A* students

Students who got top grades in their A-levels share their secrets

## Study help links and info

Can you help? Study help unanswered threadsRules and posting guidelines

## Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE