You are Here: Home >< Maths

# Statistics - measure of similarity Watch

Announcements
1. 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 and one defined by , 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. and .

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

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 11, 2016
Today on TSR

### Oxbridge

Even more elitist than everyone thought?

### Physically ill after being cheated on

Discussions on TSR

• Latest
• ## 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
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

## Groups associated with this forum:

View associated groups
Discussions on TSR

• Latest
• ## 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

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