Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    7
    ReputationRep:
    The bottling process can be adjusted so that the mean changes but the variance is unchanged (the variance is 3.2, so the standard deviation is the root of this)
    What should the mean be changed to in order to have only a 0.1% chance of a bottle having less than 700 ml of sparkling water? Give your answer correct to 1 decimal place.

    I worked this out and got 699.5 as my final answer for the new mean.
    However, I think the mark scheme is dodgy because
    (a) It got a different answer to me
    (b) It uses 0.01 as the probability first even though the question clearly states it is 0.1.
    (c) It then goes on to use 0.001 as the probability. So two incorrect probabilities used!
    Can someone work this out please and see if you get the same answer as me?
    This question comes from question 7 part (d) of the Edexcel S1 Solomon B paper.
    Offline

    22
    ReputationRep:
    (Original post by Jessika300599)
    The bottling process can be adjusted so that the mean changes but the variance is unchanged (the variance is 3.2, so the standard deviation is the root of this)
    What should the mean be changed to in order to have only a 0.1% chance of a bottle having less than 700 ml of sparkling water? Give your answer correct to 1 decimal place.

    I worked this out and got 699.5 as my final answer for the new mean.
    However, I think the mark scheme is dodgy because
    (a) It got a different answer to me
    (b) It uses 0.01 as the probability first even though the question clearly states it is 0.1.
    (c) It then goes on to use 0.001 as the probability. So two incorrect probabilities used!
    Can someone work this out please and see if you get the same answer as me?
    This question comes from question 7 part (d) of the Edexcel S1 Solomon B paper.
    0.1% is 0.1/100.
    • Thread Starter
    Offline

    7
    ReputationRep:
    (Original post by Zacken)
    0.1% is 0.1/100.
    Omg yes I didn't realise that *face palm*
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Brussels sprouts
    Useful resources

    Make your revision easier

    Maths

    Maths Forum posting guidelines

    Not sure where to post? Read the updated guidelines here

    Equations

    How to use LaTex

    Writing equations the easy way

    Student revising

    Study habits of A* students

    Top tips from students who have already aced their exams

    Study Planner

    Create your own Study Planner

    Never miss a deadline again

    Polling station sign

    Thinking about a maths degree?

    Chat with other maths applicants

    Can you help? Study help unanswered threads

    Groups associated with this forum:

    View associated groups
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • 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

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