Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta
    • Thread Starter
    Offline

    2
    ReputationRep:
    This is the question:
    A mathematics student has been asked to calculate some properties of the volumes, x cm^3, of a sample of 8 solid objects. To make the calculations easier he decides to subtract 200cm^3 from each volume. His results can be summarised as:
    Σ(x-200) = 17000
    Σ(x-200)^2 = 86000000

    I have found the coded mean (2325) and the coded standard deviation (2497). The last part is to calculate the value of Σ(x-300). Please could someone tell me how to do it or give me hints on how to do it, thanks.
    • Very Important Poster
    Offline

    21
    ReputationRep:
    Very Important Poster
    (Original post by samanthayates98)
    This is the question:
    A mathematics student has been asked to calculate some properties of the volumes, x cm^3, of a sample of 8 solid objects. To make the calculations easier he decides to subtract 200cm^3 from each volume. His results can be summarised as:
    Σ(x-200) = 17000
    Σ(x-200)^2 = 86000000

    I have found the coded mean (2325) and the coded standard deviation (2497). The last part is to calculate the value of Σ(x-300). Please could someone tell me how to do it or give me hints on how to do it, thanks.
    You've already worked out the sum of (x-200), so what will be the difference between that and the sum you're looking for?
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by SeanFM)
    You've already worked out the sum of (x-200), so what will be the difference between that and the sum you're looking for?
    Thanks but im still not sure how to do it. The answers in the back say it is 16200 but i dont know how they got it.
    • Very Important Poster
    Offline

    21
    ReputationRep:
    Very Important Poster
    (Original post by samanthayates98)
    Thanks but im still not sure how to do it. The answers in the back say it is 16200 but i dont know how they got it.
    Σ(a + b + c) = Σa + Σb + Σc, where a, b and c can be anything.

    Eg Σ(x^2 + 1) = Σx^2 + Σ 1, and the sum of n 1's is n. (1 + 1 + 1... n times).

    Now think about what has been given to you in the question and what you've worked out, and what the hint in this post is trying to tell you.
 
 
 
Poll
Do you like carrot cake?
Help with your A-levels

All the essentials

The adventure begins mug

Student life: what to expect

What it's really like going to uni

Rosette

Essay expert

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

Uni match

Uni match

Our tool will help you find the perfect course for you

Study planner

Create a study plan

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

Study planner

Resources by subject

Everything from mind maps to class notes.

Hands typing

Degrees without fees

Discover more about degree-level apprenticeships.

A student doing homework

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

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.