ABSTRACT
It is sometimes necessary to lower a patient’s blood pressure during surgery, using a hypotensive drug. Such drugs are administered continuously during the relevant phase of the operation; because the duration of this phase varies so does the total amount of drug administered. Patients also vary in the extent to which the drugs succeed in lowering blood pressure. The sooner the blood pressure rises again to normal after the drug is discontinued, the better. The data in Table 16.1 (a missing-value version of the data presented by Robertson and Armitage, 1959) relate to a particular hypotensive drug and give the time in minutes before the patient’s systolic blood pressure returned to 100mm of mercury (the recovery time), the logarithm (base 10) of the dose of drug in milligrams, and the average systolic blood pressure achieved while the drug was being administered. The question of interest is how is the recovery time related to the other two variables? For some patients the recovery time was not recorded and the missing values are indicated as NA in Table 16.1.
