the Hurst exponent reveals about time series

Inverted yield curve

Short-term rates exceed long-term, often predicts recession

Beta (finance)

Beta measures a stock's volatility relative to the market

implied volatility tells you

Implied volatility (IV) = option price / Black–Scholes model

Cronbach's alpha

Cronbach's alpha (α) measures internal consistency

Volatility smile

Implied volatility varies with strike price, contradicting Black-Scholes

Phillips curve

Phillips curve shows inverse relationship between unemployment and inflation