A: PMCC

From the OCR B MEI specification (LINK):

PLAYLIST

Bivariate Data

01 Introduction to Bivariate Data

02 Dependent & Independent Variables

03 Random, Non-Random & Control Variables

Correlation & Association

04 Correlation

05 Misleading Distributions

06 Association

The PMCC

07 The Product Moment Correlation Coefficient

08 Bivariate Normal Distribution

09 Deriving the PMCC

10 EXTENSION Alternative for Sxy

11 EXTENSION Alternative for Sxx & Syy

12 Formulae for PMCC

13 Using Summary Statistics Example 1

14 Using Summary Statistics Example 2

15 Finding the PMCC on your calculator