Computes the expected number of repeat transactions in the interval (0, vT_i] for a randomly selected customer, where 0 is defined as the point when the customer came alive.

bgnbd_nocov_expectation(r, alpha, a, b, vT_i)

bgnbd_staticcov_expectation(r, vAlpha_i, vA_i, vB_i, vT_i)

## Arguments

r shape parameter of the Gamma distribution of the purchase process scale parameter of the Gamma distribution of the purchase process shape parameter of the Beta distribution of the lifetime process shape parameter of the Beta distribution of the lifetime process Number of periods since the customer came alive Vector of individual parameters alpha Vector of individual parameters a Vector of individual parameters b

## Value

Returns the expected transaction values according to the chosen model.

## References

Fader PS, Hardie BGS, Lee, KL (2005). ““Counting Your Customers” the Easy Way: An Alternative to the Pareto/NBD Model” Marketing Science, 24(2), 275–284.

Fader PS, Hardie BGS (2013). “Overcoming the BG/NBD Model’s #NUM! Error Problem” URL http://brucehardie.com/notes/027/bgnbd_num_error.pdf.

Fader PS, Hardie BGS (2007). “Incorporating time-invariant covariates into the Pareto/NBD and BG/NBD models.” URL http://www.brucehardie.com/notes/019/time_invariant_covariates.pdf.