Hey! Sign in to get help with your study questionsNew here? Join for free to post

Statistics - measure of similarity

Announcements Posted on
Would YOU be put off a uni with a high crime rate? First 50 to have their say get a £5 Amazon voucher! 27-10-2016
    • Thread Starter

    What statistic/function can I use to measure the similarity of two sets of data? I basically want something like a correlation coefficient but that doesn't just take into account how well one predicts the other but also how similar they are. E.g. if I have two sets of data, one defined by n and one defined by 5n^2-17, the correlation coefficient for these two datasets will be 1. I'd like a statistic that would return a 1 iff the two data sets are equivalent i.e. n and n.

    Specifically, I have a model that predicts how likely an individual is to be accepted into a college based on their A-levels, and groups them into categories based on this likelihood. I also have a sample of individuals and know whether or not those individuals got accepted or not. I've used this data to produce an actual accept rate for each likelihood category, so my data looks something like:

    Modelled likelihood | Actual accept rate for that likelihood
    0% | 2%
    10% | 12%
    20% | 18.5%
    30% | 34%
    40% | 41%
    50% | 49%
    60% | 60%
    70% | 71%
    80% | 74%
    90% | 87%
    100% | 93%

    How can I measure how 'similar' these are? I imagine something similar to a standard deviation could be used, but where we don't look at the 'distance' between each data point and the average of data points but the distance between each data point and its corresponding data point in the second array...

    Any help much appreciated, sorry if this is a stupid and/or actually complicated question
Write a reply…


Submit reply


Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. Oops, you need to agree to our Ts&Cs to register
  2. Slide to join now Processing…

Updated: October 11, 2016
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.

I want...
Useful resources

Make your revision easier


Maths Forum posting guidelines

Not sure where to post? Read here first


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
Study resources

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

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