Series
finance stats
6 parts, in reading order. Each one builds on the last.
- 01
Probability: how often something happens
SEP 5 2026 · 10 min
A probability is a number between 0 and 1 that says how often something happens in the long run.
- 02
Expected value: what a risky choice is worth on average
SEP 11 2026 · 9 min
Expected value is the average result you would get if you could repeat a risky situation many times: multiply each possible outcome by its probability and add…
- 03
Mean and standard deviation: return and risk in two numbers
SEP 19 2026 · 9 min
The mean tells you where the middle of your data is, and the standard deviation tells you how far a typical value strays from that middle; in finance the first…
- 04
Covariance and correlation: why a mix is safer than its parts
SEP 27 2026 · 9 min
Covariance and correlation measure whether two things tend to move together; in a portfolio, that one number decides how much of the risk cancels out, which is…
- 05
Sharpe, Sortino and information ratio: return per unit of risk
OCT 4 2026 · 10 min
A return on its own means little until you know the risk taken to get it; these three ratios divide extra return by risk, and they differ only in what they…
- 06
Portfolio optimisation: choosing the weights
OCT 9 2026 · 8 min
Portfolio optimisation chooses how much to put in each asset so that, for the risk you accept, the expected return is as high as possible; it works because…