Functional Data>

STATISTICAL PROBLEMATICS

What can we do when we have at hand a functional dataset? This webpage proposes to answer to this question by listing various statistical problematics presented in this website (references of chapters and parts are those of our NPFDA book).

What can we do with:

  1. only a population of curves?

    Answer: predicting an unobserved categorical response from a curve:
    UNSUPERVISED CLASSIFICATION (i.e. CLUSTERING)

    (see CHAPTER 9 for more details on the nonparametric functional classification method)
  2. a population of curves and corresponding categorical responses?

    Answer: predicting a categorical response from a curve:
    SUPERVISED CLASSIFICATION (i.e. CURVES DISCRIMINATION)

    (see CHAPTER 8 for more details on the nonparametric functional discrimination method)
  3. a population of curves and corresponding scalar responses?

    Answer: predicting a scalar response from a curve via three functional methods:
    functional conditional EXPECTATION (regression),
    functional conditional MEDIAN,
    functional conditional MODE

    (see PART II for more details on the nonparametric functional prediction methods)
  4. a time series?

    Answer: forecasting a future value via three functional methods:
    functional conditional EXPECTATION (regression),
    functional conditional MEDIAN,
    functional conditional MODE

    (see PART IV for more details on the nonparametric functional methods for forecasting)

In summary

Classification of curves (PART III) Prediction: Regression, Cond. Quantiles, Cond. Mode
Supervised (discrimination) Unsupervised (clustering) Predicting scalar responses from curves (PART II) Forecasting functional time series (PART IV)
Spectrometric curves Altimetric curves (radar waves) Spectrometric curves Electricity consumption
Speech recognition Spectrometric curves El Niño (Sea Surface Temperatures)