Total no. of newborns in all 50 cells of the hypothetical hospital column in Table 4 (as posited): | 3526 |

Expected events as computed*: 167.8 | Expected risk: 167.8/3526 = 4.8% |

Observed events as posited: 300.0 | Observed risk: 300/3526 = 8.5% |

O/E: 300/167.8 | O/E ratio: 1.8 |

Expected events are calculated by applying the following formula to the 50 cells of the hypothetical hospital data in Table 4.

where

*P*is the predicted probability in cell_{i}*i*,*i*= 1, 2, 3, . . . 50, and*f*is the corresponding frequencies in the hypothetical hospital._{i}